One or more members of a class may sue or be sued as representative parties on behalf of all in a class action if both of the following occur:
Rule 1.261.Commencement of a class action
Division II: Actions, Joinder of Actions and Parties · Last amended February 15, 2002 · Last verified July 15, 2026
In one sentenceRule 1.261 sets the two-part threshold for bringing a class action in Iowa: the class must be so numerous, or otherwise constituted, that joining every member would be impractical, and the class must share a common question of law or fact.
Full Text of Rule 1.261
1.261(1) The class is so numerous or so constituted that joinder of all members, whether or not otherwise required or permitted, is impracticable.
1.261(2) There is a question of law or fact common to the class.
Plain-English Summary
Before any Iowa court certifies a class action, the case has to clear a basic gate set by rule 1.261. One or more class members can sue, or be sued, as representatives of everyone in the class only if two things are both true: joining every member individually would be impractical, given the size or makeup of the class, and there is at least one question of law or fact common to the whole class.
This is a leaner test than some other systems use at the threshold stage. Iowa's rule folds the numerosity and commonality inquiries into rule 1.261, then handles the separate question of whether the representative parties can adequately stand in for everyone else, and whether a class action serves the case well, in rule 1.262's certification standard. Rule 1.261 asks only whether a class action is possible in the first place; rule 1.262 and the factors in rule 1.263 ask whether it should go forward.
Frequently Asked Questions
What two things does a plaintiff need to show to bring a class action in Iowa?
Under rule 1.261, the class must be so numerous, or otherwise constituted, that joining all its members would be impractical, and there must be a question of law or fact common to the class.
Is there a minimum number of class members required?
Rule 1.261 does not set a fixed number. It asks whether the class is numerous or constituted in a way that makes joinder of all members impractical, which the court evaluates on the facts of each case.
Does Rule 1.261 also require that the representative parties adequately represent the class?
No, that requirement appears separately in rule 1.262(2)(c), as part of the certification standard, rather than in rule 1.261's threshold test.
What happens after a case satisfies Rule 1.261?
Satisfying rule 1.261 is only the first step. The court still holds a certification hearing under rule 1.262 and weighs the factors in rule 1.263 before deciding whether the action may proceed as a class action.
Can a class be defined by something other than a large number of members?
Yes. Rule 1.261 allows the impracticality of joinder to arise from the class being numerous, or otherwise constituted in a way that makes joining every member impractical -- the rule does not limit this to sheer size alone.
Source & verification. Rule text and the Comment are
reproduced verbatim from the Iowa Rules of Civil Procedure, adopted by the
Iowa Supreme Court. Last verified July 15, 2026.
· Official source
Also known as: iowa class action requirementsiowa rule 1.261 numerosity commonalityhow to start class action iowaiowa class action threshold test