Consolidation of lawsuits may be ordered by a court when two or more lawsuits involving the same or similar parties (plaintiff and defendant), legal issues, and factual issues are pending in the same court or in different courts in the same jurisdiction (state court system or federal court system). If the lawsuits are pending in different courts one case may be transferred to the other court, and the cases consolidated there.

Laws and rules regarding the consolidation—or transfer and consolidation—of lawsuits vary from state to state and in the federal court system.

In Iowa, the consolidation of lawsuits is governed by the Iowa Rules of Civil Procedure. Specifically, Rule 1.261 allows for the consolidation of actions when there are common questions of law or fact to promote convenience and economy in judicial administration. The court has the discretion to order consolidation if it determines that the actions involve the same parties, issues, and facts, and that such a consolidation would be just and beneficial to the parties and the court. This can occur when cases are pending in the same court or when they are in different courts within the state of Iowa. If cases are in different courts, a transfer may be necessary before consolidation can occur. The decision to consolidate is case-specific and takes into account the potential for reducing time, cost, and complexity of the legal proceedings. At the federal level, similar provisions for consolidation are found under Rule 42(a) of the Federal Rules of Civil Procedure, which also allows for consolidation when actions before the court involve a common question of law or fact.