Monthly collections ofAstropecten brasiliensiswere made at depths of 30 and 45 m. The highest number of prey in the stomach occured in summer in both 1987 and 1988. Specimens larger than4 cm in radius had mature gonads. The reproductive cycle was determined by gonad indices and histological analysis of gonads. In 1988, the species exhibited an annual reproductive cycle with spawning in December. The pyloric caecum indices showed the highest values between April and July. The relationship between gonad index and pyloric caecum index was inverse. The pyloric caecum peak occurred during the down welling period (fall and winter) when warm tropical waters (Brazil Current) were inshore. The reproductive peak coincided with the upwelling period (during spring and summer) enabling the larvae to benefit from the richer water condition when phytoplankton are more abundant.