opinion: Per Curiam.
  On December 21, 1971, the Supreme Court of New Jersey announced the adoption of Rule 1:21-7, effective January 31, 1972, establishing a graduated schedule of maximum contingent fees applicable to tort litigation conducted by New Jersey attorneys. Appellants, representing members of the New Jersey bar, brought this action to enjoin the enforcement of the rules on the grounds that they violate several provisions of the Constitution, including the Due Process and Equal Protection Clauses of the Fourteenth Amendment. The trial judge convened a three-judge court. 28 U. S. C. § 2281.
  After hearing argument on the merits, the District Court pointed out that:
  “ [Essentially the case poses a dispute between a state’s highest court and those persons authorized by that court to practice law in the state. The relationship between the parties thus is an extremely delicate one. Under such circumstances federal courts generally have considered it appropriate, before attempting any direct federal intervention at the outset, first to permit the state courts to process the dispute. Cf. Reetz v. Bozanich, 397 U. S. 82, 85-87 (1970).”
  The court added that “[a]s was true in Reetz the initial issue is whether the state constitution authorized the enactment challenged.” The court therefore granted defendant-appellee’s motion to dismiss.
  By timely motion under Fed. Rule Civ. Proc. 59 (e), appellants sought an order amending the judgment by either
  “(A) Retaining jurisdiction, but staying proceedings in this Court pending determination of the issues of state law in the courts of New Jersey, or until efforts to obtain such a determination have been exhausted; or
  “(B) Ordering that the dismissal be without prejudice, so that the suits for determination of the federal constitutional issues may be reinstituted after exhausting state recourse with respect to state law issues.” Jurisdictional Statement 10.
  The motion was denied and appellants brought this appeal.
  “[AJbstention 'does not, of course, involve the abdication of federal jurisdiction, but only the postponement of its exercise.’ ” England v. Louisiana State Board of Medical Examiners, 375 U. S. 411, 416 (1964), quoting from Harrison v. NAACP, 360 U. S. 167, 177 (1959). For that reason, we have held that a dismissal on grounds of abstention so as to permit a state court to pass on an issue of state law must not be with prejudice. Doud v. Hodge, 350 U. S. 485 (1956); Lake Carriers’ Assn. v. MacMullan, 406 U. S. 498 (1972). The proper course is for the District Court to retain jurisdiction pending the proceedings in the state courts. Lake Carriers’ Assn. v. MacMullan, supra, at 512-513; Zwickler v. Koota, 389 U. S. 241, 244-245, n. 4 (1967). Although the District Court may have intended its judgment of dismissal to be without prejudice to the right of appellants to litigate their federal claims in federal court at the conclusion of the state proceeding, the court did deny appellants’ motion for an amendment to the judgment making clear that no prejudice would attach. The motion should have been granted. Accordingly, we vacate the judgment of the District Court and remand the case for proceedings consistent with this opinion.
  So ordered.
  Rule 1:21-7 provides in part:
  “(c) In any matter where, a client’s claim for damages is based upon the alleged tortious conduct of another, including products liability claims, and the client is not a subrogee, an attorney shall not contract for, charge, or collect a contingent fee in excess of the following limits:
  “(1) 50% on the first $1000 recovered;
  “(2) 40% on the next $2000 recovered;
  “(3) 33%% on the next $47,000 recovered;
  “(4) 20% on the next $50,000 recovered;
  “(5) 10% on any amount recovered over $100,000 . . . .”
  Appellee maintained below, as it maintains before this Court, that a three-judge court need not have been convened because the constitutional question presented is insubstantial. Bailey v. Patterson, 369 U. S. 31 (1962). It insists, however, that if the claim is substantial then it must be heard by a court of three judges, 28 U. S. C. § 2281. In view of the posture of the case on this appeal, we do not, of course, express any view on the merits of the question presented.
  The validity of the District Court’s decision to abstain is not at issue on this appeal.
  “It is better practice, in a case raising a federal constitutional or statutory claim [where the doctrine of abstention is applied], to retain jurisdiction, rather than to dismiss . . . .” Zwickler, supra, at 244 n. 4.
choices: comity: civil rights comity: criminal procedure comity: First Amendment comity: habeas corpus comity: military comity: obscenity comity: privacy comity: miscellaneous comity primarily removal cases, civil procedure (cf. comity, criminal and First Amendment); deference to foreign judicial tribunals assessment of costs or damages: as part of a court order Federal Rules of Civil Procedure including Supreme Court Rules, application of the Federal Rules of Evidence, Federal Rules of Appellate Procedure in civil litigation, Circuit Court Rules, and state rules and admiralty rules judicial review of administrative agency's or administrative official's actions and procedures mootness (cf. standing to sue: live dispute) venue no merits: writ improvidently granted no merits: dismissed or affirmed for want of a substantial or properly presented federal question, or a nonsuit no merits: dismissed or affirmed for want of jurisdiction (cf. judicial administration: Supreme Court jurisdiction or authority on appeal from federal district courts or courts of appeals) no merits: adequate non-federal grounds for decision no merits: remand to determine basis of state or federal court decision (cf. judicial administration: state law) no merits: miscellaneous standing to sue: adversary parties standing to sue: direct injury standing to sue: legal injury standing to sue: personal injury standing to sue: justiciable question standing to sue: live dispute standing to sue: parens patriae standing standing to sue: statutory standing standing to sue: private or implied cause of action standing to sue: taxpayer's suit standing to sue: miscellaneous judicial administration: jurisdiction or authority of federal district courts or territorial courts judicial administration: jurisdiction or authority of federal courts of appeals judicial administration: Supreme Court jurisdiction or authority on appeal or writ of error, from federal district courts or courts of appeals (cf. 753) judicial administration: Supreme Court jurisdiction or authority on appeal or writ of error, from highest state court judicial administration: jurisdiction or authority of the Court of Claims judicial administration: Supreme Court's original jurisdiction judicial administration: review of non-final order judicial administration: change in state law (cf. no merits: remand to determine basis of state court decision) judicial administration: federal question (cf. no merits: dismissed for want of a substantial or properly presented federal question) judicial administration: ancillary or pendent jurisdiction judicial administration: extraordinary relief (e.g., mandamus, injunction) judicial administration: certification (cf. objection to reason for denial of certiorari or appeal) judicial administration: resolution of circuit conflict, or conflict between or among other courts judicial administration: objection to reason for denial of certiorari or appeal judicial administration: collateral estoppel or res judicata judicial administration: interpleader judicial administration: untimely filing judicial administration: Act of State doctrine judicial administration: miscellaneous Supreme Court's certiorari, writ of error, or appeals jurisdiction miscellaneous judicial power, especially diversity jurisdiction