Abstract During monthly samplings between September 1998 and August 2000, 3,660 specimens of Ucides cordatus (Linnaeus, 1763) (2054 males and 1606 females) were obtained and examined for size (CW = carapace width) to determine growth-age equations for each sex. This species showed a slower growth, with a marked seasonal oscillation, in females as compared to males, suggesting application of the seasonal and nonseasonal von Bertalanffy growth model, respectively. CW∞ and k constant were closely similar for the two sexes (CW∞ male = 90.3 mm; CW∞ female = 88.6 mm; kmale = 0.28; kfemale = 0.26). The age at sexual maturity was estimated to be around 3 years, while the age at legal size (CW = 60 mm) was 3.8 and 4.7 years for males and females, respectively. In the laboratory, juvenile stages did not show differences in growth rates under the same temperature and photoperiod conditions.