The article discusses the rules that determine which court has the authority to handle specific types of cases in Jordan. These rules are important because they ensure fairness and justice in legal proceedings. If a court doesn't have the right jurisdiction, it must declare so. Violating these rules can lead to cases being completely invalid. The study focuses on the subject-matter jurisdiction of the court of first instance, excluding territorial jurisdiction. It clarifies the court's authority over civil and criminal cases. The article concludes with recommendations, such as transferring the jurisdiction of special courts to the courts of first instance.