The Diocese of Lamezia Terme is a Latin Church diocese of the Catholic Church in Calabria. In 1818 the ancient see of Martirano, the former Mamertum, was united to the diocese of Nicastro. The diocese was then a suffragan of the archdiocese of Reggio in Calabria. In 1986, the historic Diocese of Nicastro had its name changed. It is currently called the Diocese of Lamezia Terme, and it is a suffragan of the Archdiocese of Catanzaro-Squillace. The name change reflects the incorporation of the comune of Nicastro into Lamezia Terme, an administrative change of 1968 on the part of the State of Italy.