MR. JUSTICE STEWART delivered the opinion of the Court.

In an action in which federal jurisdiction is based on diversity of citizenship, may the plaintiff assert a claim against a third-party defendant when there is no independent basis for federal jurisdiction over that claim? The Court of Appeals for the Eighth Circuit held in this case that such a claim is within the ancillary jurisdiction of the federal courts. We granted certiorari, 434 U. S. 1008, because this decision conflicts with several recent decisions of other Courts of Appeals.1

I

On January 18, 1972, James Kroger was electrocuted when the boom of a steel crane next to which he was walking came too close to a high-tension electric power line. The respondent (his widow, who is the administratrix of his estate) filed a wrongful-death action in the United States District Court for the District of Nebraska against the Omaha Public Power District (OPPD). Her complaint alleged that OPPD's negligent construction, maintenance, and operation of the power line had caused Kroger's death. Federal jurisdiction was based on diversity of citizenship, since the respondent was a citizen of Iowa and OPPD was a Nebraska corporation.

OPPD then filed a third-party complaint pursuant to Fed. Rule Civ. Proc. 14 (a) against the petitioner, Owen Equip

1 Fawvor v. Texaco, Inc., 546 F. 2d 636 (CA5); Saalfrank v. O'Daniel, 533 F. 2d 325 (CA6); Parker v. W. W. Moore & Sons, 528 F. 2d 764 (CA4); Joseph v. Chrysler Corp., 513 F. 2d 626 (CA3), aff'g 61 F. R. D. 347 (WD Pa.); Kenrose Mfg. Co. v. Fred Whitaker Co., 512 F. 2d 890 (CA4).

2 Rule 14 (a) provides in relevant part:

"At any time after commencement of the action a defending party, as a third-party plaintiff, may cause a summons and complaint to be served upon a person not a party to the action who is or may be liable to him for all or part of the plaintiff's claim against him. ... The person served with the summons and third-party complaint, hereinafter called the thirdparty defendant, shall make his defenses to the third-party plaintiff's

ment and Erection Co. (Owen), alleging that the crane was owned and operated by Owen, and that Owen's negligence had been the proximate cause of Kroger's death. OPPD later moved for summary judgment on the respondent's complaint against it. While this motion was pending, the respondent was granted leave to file an amended complaint naming Owen as an additional defendant. Thereafter, the District Court granted OPPD's motion for summary judgment in an unreported opinion. The case thus went to trial between the respondent and the petitioner alone.

The respondent's amended complaint alleged that Owen was "a Nebraska corporation with its principal place of busi

claim as provided in Rule 12 and his counterclaims against the thirdparty plaintiff and cross-claims against other third-party defendants as provided in Rule 13. The third-party defendant may assert against the plaintiff any defenses which the third-party plaintiff has to the plaintiff's claim. The third-party defendant may also assert any claim against the plaintiff arising out of the transaction or occurrence that is the subject matter of the plaintiff's claim against the third-party plaintiff. The plaintiff may assert any claim against the third-party defendant arising out of the transaction or occurrence that is the subject matter of the plaintiff's claim against the third-party plaintiff, and the third-party defendant thereupon shall assert his defenses as provided in Rule 12 and his counter-claims and cross-claims as provided in Rule 13."

* Under Rule 14 (a), a third-party defendant may not be impleaded merely because he may be liable to the plaintiff. See n. 2, supra; see also Advisory Committee's Notes on 1946 Amendment to Fed. Rule Civ. Proc. 14, 28 U. S. C. App., pp. 7752-7753. While the third-party complaint in this case alleged merely that Owen's negligence caused Kroger's death, and the basis of Owen's alleged liability to OPPD is nowhere spelled out, OPPD evidently relied upon the state common-law right of contribution among joint tortfeasors. See Dairyland Ins. Co. v. Mumert, 212 N. W. 2d 436, 438 (Iowa); Best v. Yerkes, 247 Iowa 800, 77 N. W. 2d 23. The petitioner has never challenged the propriety of the thirdparty complaint as such.

✦ Judgment was entered pursuant to Fed. Rule Civ. Proc. 54 (b), and the Court of Appeals affirmed. Kroger v. Omaha Public Power Dist., 523 F. 2d 161 (CA8).

ness in Nebraska." Owen's answer admitted that it was "a corporation organized and existing under the laws of the State of Nebraska," and denied every other allegation of the complaint. On the third day of trial, however, it was disclosed that the petitioner's principal place of business was in Iowa, not Nebraska," and that the petitioner and the respondent were thus both citizens of Iowa. The petitioner then moved to dismiss the complaint for lack of jurisdiction. The District Court reserved decision on the motion, and the jury thereafter returned a verdict in favor of the respondent. In an unreported opinion issued after the trial, the District Court denied the petitioner's motion to dismiss the complaint.

The judgment was affirmed on appeal. 558 F. 2d 417. The Court of Appeals held that under this Court's decision. in Mine Workers v. Gibbs, 383 U. S. 715, the District Court had jurisdictional power, in its discretion, to adjudicate the respondent's claim against the petitioner because that claim arose from the "core of 'operative facts' giving rise to both [respondent's] claim against OPPD and OPPD's claim against Owen." 558 F. 2d, at 424. It further held that the District Court had properly exercised its discretion in proceeding to decide the case even after summary judgment had been granted to OPPD, because the petitioner had concealed its Iowa citizenship from the respondent. Rehearing en banc was denied by an equally divided court. 558 F. 2d 417.

"The problem apparently was one of geography. Although the Missouri River generally marks the boundary between Iowa and Nebraska, Carter Lake, Iowa, where the accident occurred and where Owen had its main office, lies west of the river, adjacent to Omaha, Neb. Apparently the river once avulsed at one of its bends, cutting Carter Lake off from the rest of Iowa.

Title 28 U. S. C. § 1332 (c) provides that "[f]or the purposes of [diversity jurisdiction] . . ., a corporation shall be deemed a citizen of any State by which it has been incorporated and of the State where it has its principal place of business."

It is undisputed that there was no independent basis of federal jurisdiction over the respondent's state-law tort action against the petitioner, since both are citizens of Iowa. And although Fed. Rule Civ. Proc. 14 (a) permits a plaintiff to assert a claim against a third-party defendant, see n. 2, supra, it does not purport to say whether or not such a claim requires an independent basis of federal jurisdiction. Indeed, it could not determine that question, since it is axiomatic that the Federal Rules of Civil Procedure do not create or withdraw federal jurisdiction.'

In affirming the District Court's judgment, the Court of Appeals relied upon the doctrine of ancillary jurisdiction, whose contours it believed were defined by this Court's holding in Mine Workers v. Gibbs, supra. The Gibbs case differed from this one in that it involved pendent jurisdiction, which concerns the resolution of a plaintiff's federal- and statelaw claims against a single defendant in one action. By contrast, in this case there was no claim based upon substantive federal law, but rather state-law tort claims against two different defendants. Nonetheless, the Court of Appeals was correct in perceiving that Gibbs and this case are two species of the same generic problem: Under what circumstances may a federal court hear and decide a state-law claim arising between citizens of the same State? But we believe that the Court of Appeals failed to understand the scope of the doctrine of the Gibbs case.

8

The plaintiff in Gibbs alleged that the defendant union had violated the common law of Tennessee as well as the federal

Fed. Rule Civ. Proc. 82; see Snyder v. Harris, 394 U. S. 332; Sibbach v. Wilson & Co., 312 U. S. 1, 10.

8 No more than in Aldinger v. Howard, 427 U. S. 1, is it necessary to determine here "whether there are any 'principled' differences between pendent and ancillary jurisdiction; or, if there are, what effect Gibbs had on such differences." Id., at 13.

prohibition of secondary boycotts. This Court held that, although the parties were not of diverse citizenship, the District Court properly entertained the state-law claim as pendent to the federal claim. The crucial holding was stated as follows: "Pendent jurisdiction, in the sense of judicial power, exists whenever there is a claim 'arising under [the] Constitution, the Laws of the United States, and Treaties made, or which shall be made, under their Authority...,' U. S. Const., Art. III, § 2, and the relationship between that claim and the state claim permits the conclusion that the entire action before the court comprises but one constitutional 'case.' The state and federal

claims must derive from a common nucleus of operative fact. But if, considered without regard to their federal or state character, a plaintiff's claims are such that he would ordinarily be expected to try them all in one judicial proceeding, then, assuming substantiality of the federal issues, there is power in federal courts to hear the whole." 383 U. S., at 725 (emphasis in original)."

It is apparent that Gibbs delineated the constitutional limits of federal judicial power. But even if it be assumed that the District Court in the present case had constitutional power to decide the respondent's lawsuit against the petitioner,10 it does not follow that the decision of the Court of Appeals

The Court further noted that even when such power exists, its exercise remains a matter of discretion based upon "considerations of judicial economy, convenience and fairness to litigants," 383 U. S., at 726, and held that the District Court had not abused its discretion in retaining jurisdiction of the state-law claim.

10 Federal jurisdiction in Gibbs was based upon the existence of a question of federal law. The Court of Appeals in the present case believed that the "common nucleus of operative fact" test also determines the outer boundaries of constitutionally permissible federal jurisdiction when that jurisdiction is based upon diversity of citizenship. We may assume without deciding that the Court of Appeals was correct in this regard. See also n. 13, infra.