The Maryland Return of Service (ROS) is a legal document used to initiate a civil lawsuit in Maryland courts. This document is required to start a lawsuit and contains information about the plaintiff, the defendant, and the cause of action for the lawsuit. It must be filed by the plaintiff or their representative in the Maryland Circuit Court Clerk's Office. The Maryland ROS can be divided into two separate types: Original Process and Summons. The Original Process is used to inform the defendant of the lawsuit and must contain the names and addresses of both the plaintiff and the defendant. The Summons is issued by the court and is used to inform the defendant of the lawsuit and request a response. In addition to the Original Process and Summons, the Maryland ROS may also include a writ of summons, a complaint, and a certificate of service. The writ of summons informs the defendant of the plaintiff's claim, the complaint states the plaintiff's legal claim, and the certificate of service informs the court that the defendant has been properly served.