The reproductive performance of two Varunidae crabs, Cyrtograpsus angulatus and C. altimanus from Jabalí Island (40°32′S, 62°15′W), Argentina, were compared. The following reproductive variables were measured in the laboratory for fixed females of each species: realized fecundity (number of eggs/female); EW: egg dry weight (egg dry weight/number of eggs); RO: reproductive output (egg dry weight/female dry weight); RF: relative fecundity (number of eggs by female/female dry weight); and RSOM (relative size at the onset of maturity). Cyrtograpsus angulatus showed a greater realized fecundity than C. altimanus, in accordance with the greater size of the former (20.88 ± 0.66 mm and 8.52 ± 0.12 mm carapace widths, respectively). The EW, RO, and RF presented similar values for both species, whereas C. altimanus had a greater RSOM than C. angulatus.