Local, Petty Sessions and Small Claims Courts were amalgamated to form the Magistrates Court in May 2005. The reform of the courts followed on from recommendations by the Law Reform Commission, and was the most significant reform of the Western Australian lower court system in over 100 years. The Magistrates Court deals with both civil and criminal cases, including the reading of indictments, and the hearing of summary offenses. Indictable offences may be referred from the Magistrates Court to the Supreme Court.

The Magistrates Court has several registries throughout the State, established under s.8 (1) of the Magistrate's Court Act. Only certain cases can be commenced in the Court's civil jurisdiction and registry functions are performed by Police Officers.