Petitioner Willie Carter, pro se, moves pursuant to 28 U.S.C. § 2244(b)(3)(A) for an order authorizing the district court to consider a second or successive motion for a writ of habeas corpus brought under 28 U.S.C. § 2255. We write to clarify that the denial of an initial § 2255 motion on grounds of procedural default (ie., for failure to raise a claim on direct appeal, which failure is not excused by a showing of cause and prejudice) constitutes a disposition on the merits, such that any subsequent § 2255 motion will require authorization pursuant to §§ 2255 and 2244(b)(3)(A). Furthermore, the fact that a subsequent motion raises new grounds for relief has no bearing on this requirement. In this case, because the statutory requirements of §§ 2244 and 2255 are not satisfied, authorization is denied.

I.

In 1991, Carter was convicted in the United States District Court for the District of Connecticut (Peter C. Dorsey, Judge) for possession of a firearm as a convicted felon and was sentenced to a 235-month term of imprisonment. Carter was represented by counsel at trial and in his direct appeal. That appeal was unsuccessful, see United States v. Carter, 979 F.2d 846 (2d Cir.1992) (table) (affirming district court).

In 1993, Carter filed a pro se § 2255 motion challenging his conviction on the sole ground that the indictment was defective because the grand jury was not comprised of a “fair and representative cross-section of the public.” The district court denied the § 2255 motion on grounds of procedural default— that is, because Carter neither raised the grand jury issue at trial or on appeal, nor demonstrated cause for and prejudice arising from his failure to do so. Carter did not appeal the district court’s denial of the motion.

[*204] On May 7, 1998, Carter filed in this Court the instant authorization motion, ^[1] challenging his 1991 conviction on three new grounds: (1) improper enhancement of his sentence, under 18 U.S.C. § 924(e), because his civil rights have been restored with respect to the three prior state convictions upon which the sentencing enhancement was based; ^[2] (2) improper enhancement of his sentence because his prior judgments of conviction had been entered pursuant to allegedly involuntary guilty pleas, see Boykin v. Alabama, 395 U.S. 288, 89 S.Ct. 1709, 23 L.Ed.2d 274 (1969); and (3) ineffective assistance of trial and appellate counsel. ^[3] The motion brought no new evidence to our attention, and Carter’s memorandum of law does not refer to any new principles of constitutional law. See 28 U.S.C. § 2255 ¶8 (limiting authorization to second or successive motions based on new evidence or new constitutional law).

II.

The Antiterrorism and Effective Death Penalty Act, Pub.L. No. 104-132, 110 Stat. 1214 (1996) (“AEDPA”), amended 28 U.S.C. § 2255 to require a movant, prior to filing a second or successive motion for habeas corpus relief in the district court, to obtain an order from the relevant Court of Appeals authorizing consideration by a district court of that motion. See 28 U.S.C. §§ 2255 ¶ 8, 2244(b)(3)(A). Authorization will be granted only if the second or successive motion is based on:

(1) newly discovered evidence that, if proven and viewed in light of the evidence as a whole, would be sufficient to establish by clear and convincing evidence that no reasonable fact finder would have found the movant guilty of the offense, or

(2) a new rule of constitutional law, made retroactive to cases on collateral review by the Supreme Court, that was previously unavailable.

28 U.S.C. § 2255 ¶ 8.

However, “[t]he AEDPA does not define ‘second or successive motion’ in [section 2255] or ‘second or successive habeas corpus application’ in [section 2254].” Galtieri v. United States, 128 F.3d 33, 37 (2d Cir.1997). In our efforts to define the meaning and scope of these terms, we have recognized instances in which a subsequent § 2255 motion or § 2254 petition was not properly considered “second or successive.” See, e.g., id. at 37-38 (holding that when a first § 2255 motion succeeds in obtaining a sentence amendment, a subsequent motion will be considered a “first” motion to the extent that it challenges a new or amended component of the sentence, and a “second” motion to the extent that it challenges either a component of the original, unamended sentence or the underlying conviction); Chambers v. United States, 106 F.3d 472, 474 (2d Cir.1997) (“[A] petition asserting a claim to relief available under 28 U.S.C. § 2255 is not a ‘second or successive’ application where the prior petitions) sought relief available only under 28 U.S.C. § 2241.”); Camarano v. Irvin, 98 F.3d 44, 47 (2d Cir.1996) (“[A] petition filed after a prior petition is dismissed without prejudice for failure to exhaust state remedies is not a ‘second or successive’ petition within the meaning of § 2244,” because there[*205] has been no federal adjudication on the merits). ^[4] Additionally, we have remanded to the district court for a determination of whether a proposed motion or petition is indeed “second or successive” when it was unclear (1) whether the prior habeas petition was dismissed on the merits or (2) whether the prior habeas petition even addressed the same conviction that was the subject of the assert-edly successive petition. See Thomas v. Superintendent, 136 F.3d 227, 229 (2d Cir.1997).

The authorization motion now before us falls outside the scope of our prior rulings. Carter’s first unsuccessful motion, in 1993, was made pursuant to § 2255 and it was not dismissed without prejudice or for failure to exhaust. Moreover, the 1993 motion and the instant motion both clearly challenge the same conviction. The question presented, therefore, is whether the denial of Carter’s first motion for procedural default was a disposition on the merits for purposes of the AEDPA’s second or successive motion provisions. Mindful of the law of other circuits relating to procedural default and successive petitions under § 2254, as well as of the evolution of habeas law prior to' passage of the AEDPA, we answer this question in the affirmative.

Our sister circuits have held that the denial of a first § 2254 petition for procedural default, which default is not overcome by a showing of cause and prejudice, “must be regarded as a determination on the merits in examining whether a subsequent petition is successive.” Bates v. Whitley, 19 F.3d 1066, 1067 (5th Cir.1994); accord Hawkins v. Evans, 64 F.3d 543, 546-47 (10th Cir.1995) (quoting Bates); Howard v. Lems, 905 F.2d 1318, 1322-23 (9th Cir.1990) (dismissal for procedural default, unlike dismissal for failure to exhaust state remedies, is a disposition on the merits); cf. Shaw v. Delo, 971 F.2d 181, 184 (8th Cir.1992) (holding that a district court may review successive or abusive claims but only if petitioner establishes cause and prejudice). Although these decisions predate the AEDPA and concerned § 2254 petitions, the petition-limiting rules they interpreted were equally applicable to successive § 2255 motions and have since been codified, and even strengthened, by .the AEDPA. ^[5] Accordingly, we hold that a denial[*206] on grounds of procedural default constitutes a disposition on the merits and thus renders a subsequent § 2254 petition or § 2255 motion “second or successive” for purposes of the AEDPA.

Furthermore, although Bates and its companions addressed successive petitions based on previously raised grounds, and Carter advances in his successive motion new grounds not previously raised, that distinction does not affect our conclusion that a denial of a first motion or petition on grounds of procedural default causes a subsequent motion or petition to come within the ambit of the.AEDPA’s “second or successive” provisions. Cf . McCleskey v. Zant, 499 U.S. 467, 489-95, 111 S.Ct. 1454, 113 L.Ed.2d 517 (1991) (effectively eliminating former distinction between new and previously heard grounds by collapsing tests for procedural default and abuse of the writ).

III.

Finding the instant proposed § 2255 motion to be a second or successive motion, we conclude that authorization is not warranted under the AEDPA because Carter’s claims are clearly based neither on newly discovered evidence nor on a new rule of constitutional law. Accordingly, the authorization motion must be, and hereby is, denied.