The corticioid fungi from Santa Catarina Island mangroves were surveyed, and 42 specimens corresponding to 15 species and 13 genera were identified. The most commonly found species was Hjortstamia crassa, and the Itacorubi mangrove was the area where more specimens were found (17 out of 42 specimens). Most of the specimens were collected on dead wood, and the most common host was Avicennia schaueriana. Six species were previously unknown from mangroves around the world; Phanerochaete subglobosa is recorded for the first time outside Asia, Hjortstamia amethystea is newly reported from Southern Brazil, and four species are new records from the State of Santa Catarina. Taxonomic remarks are given for the treated species, and an updated checklist of xylophilous fungi and pseudofungi (Myxomycetes) known from Santa Catarina Island mangroves is provided.