Lousada (European Portuguese pronunciation: [loˈzaðɐ] ^ⓘ) is a town and municipality of the Porto district, in northern Portugal. The population in 2011 was 47,387, in an area of 96.08 km².

It includes the site of Ancient Magnetum (Portuguese Magneto), in the civil parish Meinedo, which briefly was a short-lived Suebi-Galician bishopric and is now a Latin Catholic titular see.

The town in named after the Luso-Galician Lozada family.

In 569, as Diocese of Magnetum (Latin) / Magneto (Curiate Italiano and Portuguese) / Magneten(sis) (Latin adjective) was established on territory of the Kingdom of the Suebi in Galicia, split off from the Archdiocese of Braga, its apparent Metropolitan.

In 585, when the kingdom was annexed by the Visigoths, and was turned into the sixth province of the Visigothic Kingdom of Hispania, the bishopric was suppressed, its territory being reassigned to establish the Diocese of Portucale (present see of Porto).

Its only recorded residential bishop was :

The diocese was nominally restored in 1969 as Latin Catholic Titular bishopric of Magnetum (Latin) / Magneto (Curiate Italian) / Magneten(sis) (Latin adjective).

It has had the following incumbents, of the fitting Episcopal (lowest) rank with an archiepiscopal (current) exception :