OPINION

TASHIMA, Circuit Judge:

Alfonso Manuel Blake, a state prisoner, filed a habeas corpus petition under 28 U.S.C. § 2254 based on, inter alia, alleged ineffective assistance of trial counsel ("IAC"). Because this claim was not exhausted, Blake moved for a stay and abeyance under Rhines v. Weber, 544 U.S. 269, 125 S.Ct. 1528, 161 L.Ed.2d 440 (2005), so that he could return to state court and exhaust this claim. The district court denied the motion. We must decide whether Blake's explanation for failure to exhaust this claim met the "good cause" requirement of Rhines. Because we answer that question in the affirmative, we reverse and remand.

I.

Blake was convicted in Nevada state court of two counts of first-degree murder with the use of a deadly weapon and sentenced to death.1 The convictions were affirmed on appeal. Blake then filed a state habeas petition, which was denied. The denial was affirmed on appeal.

Blake then timely filed this federal petition. In his amended petition, he argued for the first time that, among other things, his trial counsel was ineffective for failing to discover and present to the jury evidence of Blake's abusive upbringing and history of mental illness.2

Blake's amended petition was a "mixed petition," i.e., it contained both exhausted and unexhausted claims. As such, it was subject to dismissal under Rose v. Lundy, 455 U.S. 509, 102 S.Ct. 1198, 71 L.Ed.2d 379 (1982). Blake thereafter filed a Rhines motion for a stay and abeyance of his mixed petition so that he could return to state court fully to exhaust his unexhausted claims. He argued that he had good cause for failing to exhaust his trial-counsel IAC claim because he received ineffective assistance of counsel during state post-conviction proceedings. He argued that his state post-conviction counsel was ineffective because she "failed to conduct any independent investigation" and discover "easily identifi[able]" claims that Blake had endured "outrageous and severe sexual, physical and emotional abuse as a child" and "suffered from organic brain damage and psychological disorders." In other words, Blake argued that his state post-conviction counsel was ineffective for failing to discover the same evidence underlying his trial-counsel IAC claim.

The district court denied Blake's motion for a stay and abeyance on the sole ground that Blake failed to establish good cause. It held that IAC by post-conviction counsel did not constitute good cause because it was an excuse "that could be raised in virtually every case." In denying a subsequent motion for reconsideration, the district court held that Blake's excuse was "too generic" and that, as a matter of law, "Strickland-type claim[s] of ineffective assistance of post-conviction counsel cannot constitute good cause for failing to exhaust."

The district court ordered Blake to abandon his unexhausted claims or face dismissal under Lundy. Blake elected not to dismiss his unexhausted claims and the district court dismissed his petition. Blake timely appeals.

II.

We review the district court's denial of a stay and abeyance for abuse of discretion. Rhines, 544 U.S. at 278-79, 125 S.Ct. 1528.

III.

In Rhines, the Supreme Court held that when a habeas petitioner files a mixed petition, a district court may stay the petition and hold it in abeyance to allow the petitioner to return to state court and present his unexhausted claims. Id. at 275-76, 125 S.Ct. 1528. Before Rhines, the Supreme Court had adopted a rule of "total exhaustion," requiring that all claims in a federal habeas petition be exhausted in state court before a federal court could act on the petition. See Lundy, 455 U.S. at 522, 102 S.Ct. 1198. Under Lundy, a district court had to "dismiss such `mixed petitions,' leaving the prisoner with the choice of returning to state court to exhaust his claims or of amending or resubmitting the habeas petition to present only exhausted claims to the district court." Id. at 510, 102 S.Ct. 1198.

The Lundy rule, however, became problematic once Congress enacted the Antiterrorism and Effective Death Penalty Act of 1996 ("AEDPA"). "AEDPA preserved Lundy's total exhaustion requirement," but also "imposed a 1-year statute of limitations on the filing of federal petitions." Rhines, 544 U.S. at 274, 125 S.Ct. 1528 (citing 28 U.S.C. §§ 2254(b)(1)(A), 2244(d)). "As a result of the interplay between AEDPA's 1-year statute of limitations and Lundy's dismissal requirement, petitioners who come to federal court with `mixed' petitions run the risk of forever losing their opportunity for any federal review of their unexhausted claims." Id. at 275, 125 S.Ct. 1528.

Responding to "the gravity of this problem and the difficulty it has posed for petitioners and federal district courts alike," id. at 275, 125 S.Ct. 1528, the Court in Rhines approved the use of a stay and abeyance in "limited circumstances," id. at 277, 125 S.Ct. 1528, stating that:

Id. at 278, 125 S.Ct. 1528. The Court explained that restricting the availability of the stay-and-abeyance procedure to only those cases that satisfy this three-part test protects AEDPA's "twin purposes" of promoting finality of sentences and encouraging petitioners to exhaust their claims in state court before filing in federal court. Id. at 277-78, 125 S.Ct. 1528.

Here, the district court denied Blake's motion for a stay and abeyance on the sole ground that Blake did not establish good cause for his failure to exhaust—the first prong of the Rhines test. The State agreed at oral argument that the second and third prongs of the Rhines test had been established. Thus, the only issue before us is whether Blake made a sufficient showing of good cause.

A.

There is little authority on what constitutes good cause to excuse a petitioner's failure to exhaust. In Rhines, the Supreme Court did not explain the standard with precision. See 544 U.S. at 275-78, 125 S.Ct. 1528. The Court has since addressed the meaning of good cause in only one other case, recognizing in dicta that "[a] petitioner's reasonable confusion about whether a state filing would be timely will ordinarily constitute `good cause'" to excuse his failure to exhaust. Pace v. DiGuglielmo, 544 U.S. 408, 416, 125 S.Ct. 1807, 161 L.Ed.2d 669 (2005) (citing Rhines, 544 U.S. at 278, 125 S.Ct. 1528).

Similarly, our cases on the meaning of good cause under Rhines are also sparse. In Jackson v. Roe, 425 F.3d 654 (9th Cir. 2005), we held that good cause does not require a showing of "extraordinary circumstances." Id. at 661-62. In Wooten v. Kirkland, 540 F.3d 1019 (9th Cir.2008), we held that a petitioner did not establish good cause simply by alleging that he was "under the impression" that his claim was exhausted. Id. at 1024. We explained that accepting as good cause the mere "lack of knowledge" that a claim was exhausted "would render stay-and-abey orders routine" because "virtually every habeas petitioner" represented by counsel could assert that he was unaware of his attorney's failure to exhaust. Id.

Notably, neither Jackson nor Wooten addresses whether IAC by post-conviction counsel could amount to good cause under Rhines. The only time that either opinion discusses IAC in the Rhines' good cause context is when this court noted that the petitioner in Wooten had not "developed any ineffective assistance of counsel argument." 540 F.3d at 1024 n. 2. In fact, no circuit has directly addressed whether state post-conviction IAC can constitute good cause under Rhines. Wagner v. Smith, 581 F.3d 410 (6th Cir.2009), perhaps comes the closest, recognizing in dicta that a petitioner "seem[ed] to have a compelling `good cause' argument that his appellate counsel was ineffective for failing to raise [the petitioner's unexhausted] claims on appeal." Id. at 419 nn. 4, 5. We now consider the question.

B.

In rejecting Blake's good cause argument, the district court analogized it to the good cause theory rejected in Wooten:

This analogy misinterprets Wooten and ignores the equitable nature of the good cause standard. In Wooten, we held that a mere "lack of knowledge" did not constitute good cause because "virtually every habeas petitioner, at least those represented by counsel, could argue that he thought his counsel had raised an unexhausted claim." 540 F.3d at 1024. In other words, we held that unspecific, unsupported excuses for failing to exhaust—such as unjustified ignorance—did not satisfy the good cause requirement. We did not hold that the good cause inquiry involves considering how frequently a particular type of excuse, viewed in the abstract, could be raised.

On reconsideration, the district court's rejection of Blake's good cause contention was even more categorical. It held that, as a matter of law, ineffective assistance of post-conviction counsel can never constitute good cause under Rhines. Thus, the district court doubly erred: first, by measuring good cause by considering only how often the type of good cause Blake asserted could be raised; and second, by holding categorically that post-conviction IAC could never constitute good cause.

It is true that a "stay and abeyance should be available only in limited circumstances"; routinely granting stays would undermine the AEDPA's goals of encouraging finality and streamlining federal habeas proceedings. Rhines, 544 U.S. at 277, 125 S.Ct. 1528. But this concern does not require limiting the definition of good cause to only those excuses that arise infrequently. Factors (2) and (3) of the Rhines test itself—that the "unexhausted claims are potentially meritorious," and that "there is no indication that the petitioner engaged in intentionally dilatory litigation tactics," id. at 278, 125 S.Ct. 1528— are designed, together with the first factor, to ensure that the Rhines stay and abeyance is not, contrary to the district court's concern, available "in virtually every case." When this three-part test is satisfied, there is no overriding concern of further limiting the availability of a stay and abeyance because "[i]n such a case, the petitioner's interest in obtaining federal review of his claims outweighs the competing interests in finality and speedy resolution of federal petitions." Id.

C.

The good cause element is the equitable component of the Rhines test. It ensures that a stay and abeyance is available only to those petitioners who have a legitimate reason for failing to exhaust a claim in state court. As such, good cause turns on whether the petitioner can set forth a reasonable excuse, supported by sufficient evidence, to justify that failure. See Pace, 544 U.S. at 416, 125 S.Ct. 1807 ("A petitioner's reasonable confusion ... will ordinarily constitute `good cause' [under Rhines]...." (emphasis added)).3 An assertion of good cause without evidentiary support will not typically amount to a reasonable excuse justifying a petitioner's failure to exhaust. In Wooten, for example, the petitioner's excuse that he was "under the impression" that his claim was exhausted was not a reasonable excuse because no evidence indicated that the petitioner's ignorance was justified. To the contrary, the petitioner's attorney sent him a copy of his state petitioner which did not mention the unexhausted claim, and the petitioner did not argue that his attorney provided ineffective assistance for failing to include the claim. 540 F.3d at 1024 n. 2; see also King v. Ryan, 564 F.3d 1133, 1138 (9th Cir.2009) (holding that the district court did not abuse its discretion in finding that the petitioner did not establish good cause when his factual allegations were "insufficiently detailed").

While a bald assertion cannot amount to a showing of good cause, a reasonable excuse, supported by evidence to justify a petitioner's failure to exhaust, will. Blake argued that he failed to exhaust his trial-counsel IAC claim because his state post-conviction counsel "failed to conduct any independent investigation or retain experts in order to" discover the facts underlying his trial-counsel IAC claim; namely, evidence that Blake "was subjected to outrageous and severe sexual, physical and emotional abuse as a child," and "suffered from organic brain damage and psychological disorders."

Blake supported his good cause argument with evidence of his abusive upbringing and history of mental illness, compiled by his federal post-conviction counsel.4 For example, Blake provided a neuropsychological and psychological evaluation report that highlighted "numerous neuropsychiatric and psychiatric conditions [Blake suffered from] at the time of the homicides," none of which was presented to the jury or to the state court.5

Blake also submitted a declaration by the private investigator hired by his state post-conviction attorney stating that within a week of receiving "thousands of pages of discovery on Blake's case," Blake's state post-conviction attorney told the investigator "that [his] services were no longer needed." The investigator declared that he "did not have a chance to speak with a single witness on Blake's case because it was over before [he] finished [his] review of the discovery materials."

Blake also provided thirteen declarations from Blake's family and friends. Most of them described the abhorrent conditions of Blake's upbringing and family history, in extensive and gruesome detail. None of these witnesses was contacted by Blake's state post-conviction attorney.6 And no evidence of Blake's background was ever presented to the Nevada state courts. This is a sufficient showing that Blake's state post-conviction counsel's performance was defective under the standard of Strickland v. Washington, 466 U.S. 668, 687, 104 S.Ct. 2052, 80 L.Ed.2d 674 (1984).

In light of that showing, we hold that the district court abused its discretion in concluding that Blake had failed to establish good cause for his failure to exhaust. Blake's showing of good cause was not a bare allegation of state post-conviction IAC, but a concrete and reasonable excuse, supported by evidence that his state post-conviction counsel failed to discover, investigate, and present to the state courts the readily available evidence of Blake's abusive upbringing and compromised mental condition.

Our holding, that IAC by post-conviction counsel can be good cause for a Rhines stay, is consistent with and supported by the Supreme Court's recent opinion in Martinez v. Ryan, ___ U.S.___, 132 S.Ct. 1309, 182 L.Ed.2d 272 (2012), in which it established a limited exception to the rule of Coleman v. Thompson, 501 U.S. 722, 753, 111 S.Ct. 2546, 115 L.Ed.2d 640 (1991), that IAC by state post-conviction counsel "at initial-review collateral proceedings may establish cause for a prisoner's procedural default of a claim of ineffective assistance at trial." 132 S.Ct. at 1315. We believe that good cause under Rhines, when based on IAC, cannot be any more demanding than a showing of cause under Martinez to excuse state procedural default.7 Unlike a successful showing of cause under Coleman and Martinez, an IAC-based showing of good cause under Rhines only permits a petitioner to return to state court—not bypass the state court as would be the case under Coleman—to exhaust his unexhausted claims. Because a Rhines stay and abeyance does not undercut the interests of comity and federalism embedded in our habeas jurisprudence, a Rhines petitioner arguing IAC-based good cause is not required to make any stronger a showing of cause than a Coleman/Martinez petitioner. Id. at 1318 (stating that "cause" is established when a petitioner's post-conviction counsel is "ineffective under the standards of Strickland"); see also Detrich v. Ryan, 740 F.3d 1237, 1243-45 (9th Cir.2013) (en banc) (plurality opinion) (discussing the showing of "cause" required under Martinez and Trevino v. Thaler, ___ U.S. ___, 133 S.Ct. 1911, 1918, 185 L.Ed.2d 1044 (2013)).

In sum, we hold that the Rhines standard for IAC-based cause is not any more demanding than the cause standard articulated in Martinez. The district court applied an erroneous legal standard in concluding that Blake failed to meet the Rhines good cause standard. It therefore abused its discretion in denying a stay and abeyance. See United States v. Hinkson, 585 F.3d 1247, 1259 (9th Cir.2009) (en banc) ("A district court would necessarily abuse its discretion if it based its ruling on an erroneous view of the law...." (quoting Cooter & Gell v. Hartmarx Corp., 496 U.S. 384, 405, 110 S.Ct. 2447, 110 L.Ed.2d 359 (1990))). Here, Blake's showing of state post-conviction IAC satisfies the Rhines good cause standard.

IV.

The judgment of the district court dismissing Blake's habeas petition is reversed and the case is remanded with instructions to grant the stay and abeyance and for further proceedings consistent with this opinion.8

REVERSED and REMANDED with directions.