Growth and sexual maturity in Saccostrea palmula were studied between May 1998 and May 1999, in Morales estuary, Punta Morales, Puntarenas, Costa Rica (n=540 individuals according to sample size equation). The weight-length relationship for the population was Pt = 2.13 x 10^-2 Lt^1.6602 and von Bertalanffy growth function was Lt = 68.2 (1- e ^{-0.1577 t}). The mean sex ratio was 1.00 male: 0.92 females with sexually mature individuals found throughout the year. Spawning activity was highest between November and January. The mean condition index (IC = PCF/PV x 100) for the population was 121.53 ± 2.24 and the mean meat yield was 10.32 ± 1.64 %