Ten parastacid species inhabit South American continental waters, grouped in the generaSamastacus, VirilastacusandParastacus.The sexuality of these species is one of the most unknown and controversial features of their biology. This article gives updated information about these species sexuality. Information is also provided on the geographic distribution, habitat and lifestyle of each of these parastacids. Three patterns of sexuality are distinguished: (1) gonochorism, in the lake populations ofS. spinifronsandV. araucanius;(2) permanent intersexuality inP. pugnax, P. varicosus, P. pilimanus, P. defossusandP. saffordi;and (3) partial protandric hermaphroditism in the fluvial populations ofS. spinifronsandP. nicoleti.None of these patterns can be assigned toP. laevigatusandP. brasiliensissince no studies of this kind are available forP. laevigatus, and those conducted onP. brasiliensisyield contradictory results.