Rule 3: Commencing an Action

To start a federal lawsuit, you file a complaint with the clerk of the court. The moment the complaint is filed, the case officially begins. This is important because it determines whether your claim was brought within the statute of limitations.

For federal claims, filing the complaint stops the statute of limitations clock. However, if you are bringing a state-law claim in federal court (for example, under diversity jurisdiction), you look to the law of the state where the court sits to determine whether filing alone is enough to toll the statute of limitations, or whether you also need to serve the defendant within a certain time.

Rule 3 works hand-in-hand with Rule 4(m), which requires that the defendant be served within 90 days after the complaint is filed. If you file on time but fail to serve within the 90-day window, the court may dismiss the action without prejudice.