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 South Dakota, the consolidation of lawsuits is governed by state statutes and rules of civil procedure. According to SDCL 15-6-42(a), when actions involving a common question of law or fact are pending before the court, it may order a joint hearing or trial of any or all the matters in issue in the actions, consolidate the actions, or issue any other orders to avoid unnecessary costs or delay. This means that if two or more lawsuits share the same parties, legal issues, or factual issues, and are pending in the same court or different courts within South Dakota, the court has the authority to consolidate these cases to streamline the process and promote judicial efficiency. The decision to consolidate is at the discretion of the court, which will consider whether consolidation would be beneficial to the parties and the court system. If the cases are in different courts, one case may be transferred to another court for consolidation. The federal court system has a similar rule under the Federal Rules of Civil Procedure Rule 42(a), which allows for consolidation of cases that involve common questions of law or fact to avoid unnecessary costs or delay.