Rule 86.Effective Dates

Last amended December 1, 2007 · Last verified June 30, 2026

In one sentenceRule 86 fixes the effective dates of the Federal Rules and their amendments, providing that they govern proceedings begun after they take effect and pending actions as well, except where applying them to a pending case would be infeasible or work an injustice.

Full Text of Rule 86

Text sizeJump to: (a) (b)

(a) In General. These rules and any amendments take effect at the time specified by the Supreme Court, subject to 28 U.S.C. § 2074. They govern:

(1) proceedings in an action commenced after their effective date; and

(2) proceedings after that date in an action then pending unless:

(A) the Supreme Court specifies otherwise; or

(B) the court determines that applying them in a particular action would be infeasible or work an injustice.

(b) December 1, 2007 Amendments. If any provision in Rules 1-5.1, 6-73, or 77-86 conflicts with another law, priority in time for the purpose of 28 U.S.C. § 2072(b) is not affected by the amendments taking effect on December 1, 2007.

End

Amendment History

(Amended December 27, 1946, effective March 19, 1948; December 29, 1948, effective October 20, 1949; April 17, 1961, effective July 19, 1961; January 21, 1963, and March 18, 1963, effective July 1, 1963; April 30, 2007, effective December 1, 2007.)

Plain-English Summary

Rule 86 is the transition rule. It records when the original rules took effect — September 16, 1938 — and provides that later amendments take effect on the dates the Supreme Court sets when it transmits them to Congress, after the statutory waiting period.

The rule also handles the changeover for pending cases. Amendments govern not only actions filed after their effective date but also proceedings then pending, unless the Supreme Court specifies otherwise or the court determines that applying a change to a particular pending action would not be feasible or would work an injustice — in which case the former rule applies.

Frequently Asked Questions

When did the Federal Rules of Civil Procedure take effect?

September 16, 1938; later amendments take effect on the dates set when they are adopted, generally governing pending cases too (Rule 86).

Do amendments always apply to cases already pending when they take effect?

Usually, but not always. An amendment applies to a pending action unless the Supreme Court specifies otherwise or the court finds that applying it to that particular case would not be feasible or would work an injustice — in which case the former rule keeps governing that case.

Source & verification. The rule text and amendment history are reproduced verbatim from the official Federal Rules of Civil Procedure (Fed. R. Civ. P. 86), a public-domain work of the U.S. Government. Prescribed by the United States Supreme Court under the Rules Enabling Act. The plain-English summary is original and written by us. Last verified June 30, 2026. · Official source

Also known as: FRCP 86Fed. R. Civ. P. 86effective dateswhen the rules take effect