Artículo de publicación WOSSerranus flaviventris(Cuvier,1829)isacommonspecieswidedistributedanddocumentedinthe Greater Caribbean and South America. Four specimens were captured at 1 m depth in Seybaplaya, Campeche, Mexico, in August and September 2017. The present note constitutes the first record for Mexico and extends the previous distribution of the species in about 1100 km, from the Greater Caribbean and South America into the Gulf of Mexico. The family Serranidae comprises 5 subfamilies, 73 genera and 522 species that are distributed in tropical and temperate seas worldwide (Burhanuddin et al. 2017). Thirty species of the genus Serranus are currently recognized, 22 of which inhabit the Atlantic Ocean (Wirtz & Iwamoto 2016). Fourteen species of the genus are recorded in the western Atlantic (Heemstra et al. 2002; McEachran 2009; Carvalho-Filio and Ferreira 2013; Wirtz & Iwamoto 2016), eight of which: Serranus annularis (Günter, 1880), S. atrobranchus (Cuvier, 1829), S. baldwini (Evermann & Marsh, 1899), S. phoebe (Poey, 1851), S. subligarius (Cope, 1870), S. tabacarius (Cuvier, 1829), S. tigrinus (Bloch, 1790) and S. tortugarum (Longley, 1935), have been reported in Mexican Atlantic and Caribbean waters (SchmitterSoto et al. 2000; González-Gándara and Arias-González 2001; Del Moral-Flores et al. 2013; Robertson et al. 2016). Serranus flaviventris (Cuvier, 1829) is a common species widely distributed and reported from the Greater Caribbean and South America (Weinstein and Heck 1979; Meisler 1987; Heemstra et al. 2002; Pina-Amargós et al. 2012). In this paper, we report the first record of S. flaviventris from Mexico, extending its previous distribution into the Gulf of Mexico.