Rules 41 to 101, inclusive, shall govern all proceedings in actions brought after their effective date, and also all further proceedings in actions then pending, except to the extent that in the opinion of the court their application in a particular action pending when the Rules take effect would not be feasible or would work injustice, in which event the former procedure applies.
Rule 41.06.Rules--Application to Pending Actions.
Rule 41: General · Last amended September 1, 1972 · Last verified July 22, 2026
In one sentenceThis rule explains that the civil procedure rules govern actions filed after their effective date and also apply to further steps in already-pending cases, unless applying them would be impractical or unfair to a specific pending case.
Full Text of Rule 41.06
Amendment History
Adopted Feb. 1, 1972, eff. Sept. 1, 1972.
Official Comment
This is substantially the same as prior Rule 41.08. Compare: Rule 86 of the Federal Rules of Civil Procedure.
Plain-English Summary
New rules always raise a question: what happens to cases already in the pipeline when the rules change? Rule 41.06 answers it. Rules 41 through 101 govern all proceedings in actions brought after their effective date, and they also govern further proceedings in actions that were already pending. The only exception is where applying the new rules to a particular pending action would not be workable, or would work an injustice — in that event, the older procedure applies instead.
This gives courts flexibility instead of a rigid switchover date. A case that was well along under the old procedure when a new rule took effect does not have to be forced awkwardly into the new framework if doing so would create real unfairness or practical problems; the court can keep using the earlier procedure for that case.
Frequently Asked Questions
Do new civil procedure rules apply to cases that were already filed before the rules took effect?
Yes, generally. Rule 41.06 states that the rules govern further proceedings in actions pending when the rules take effect, in addition to new actions filed afterward.
Is there any exception to applying new rules to pending cases?
Yes. If applying the rules to a particular pending action would not be feasible or would work an injustice, the former procedure applies instead for that action.
Who decides whether applying a new rule to a pending case would be unfair?
The rule leaves that judgment to the court handling the action, based on the circumstances of that particular case.
Does this rule apply to actions filed after the rules took effect?
Yes. Those actions are governed by the rules without the exception that applies to already-pending cases, since the exception is tied to cases pending at the time of the change.
Is there a comparable rule in federal practice?
Missouri’s rule addresses the same transition problem that the federal rules address for actions pending when the federal rules took effect, though Missouri’s version is its own text adopted for state practice.
Source & verification. Rule text and amendment history are
reproduced verbatim from the Missouri State & Federal Court Rules, adopted by the
Supreme Court of Missouri. Last verified July 22, 2026. ·
Official source
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