The genus Sinnamarynus Maldonado Capriles and Bérenger, 1996 (Hemiptera: Heteroptera: Reduviidae), originally placed into the subfamily Reduviinae, is transferred to the subfamily Peiratinae. Dorsal habitus and the male genitalia of the type species, S. rasahusoides Maldonado Capriles and Bérenger, 1996 are illustrated. The genus and species are recorded for the first time from Peru.