A complaint is the initial pleading that starts a civil action.  It states the basis for the court’s jurisdiction, the basis for the plaintiff’s claim, and the demand for relief.  In some states, this pleading is also called a petition. Under criminal law, complaint is a formal charge accusing a person of an offense.  It is a formal legal document that sets out the facts and legal reasons that the filing party believes are sufficient to support a claim against another person, persons, entity or entities that entitles the plaintiff a remedy in the form of money damages or injunctive relief.

Certain specific types of criminal cases are commenced by the filing of a criminal or felony complaint.  In the United States, the complaint is often associated with misdemeanor criminal charges presented by the prosecutor without the grand jury process.  Generally, a complaint submitted to a court must be accompanied by a Case Information Statement.  The case information sheet sets forth specific key information about the case and the lawyers representing the parties.  This allows the judge to determine the deadlines to be set for different phases of the case, as it proceeds.