A revision is provided for the Cuban endemic tenebrionid genus Trimytcmtron. Material of Ardoin's five previously described species (Trimytalltron decui, poeyi, cub anum, viiiai and negrai) is compared with the extensive series of the senior author's collection (O.H.G). Eight new species are herein described and illustrated. Also their genitalia are illustrated, as well as some of the previously described species not illustrated by Ardoin in his original descriptions. Material from several eastern localities assigned to T. decui are not exactly identical, showing some variations at subspecific level. Although these variations are mentioned, they are not described. The same situation applies to populations assigned to the new species described from the northern part of Santa Clara (the cave complex of Caguanes). Genitalia of six of the eight new species are herein illustrated as are those of T. decui and T. poeyi . Photographs of the eight new taxa are also provided; as well as a synoptic table of the principal diagnostic characters of all taxa of the genus.