Gametogenic activity of the cockle Cerastoderma glaucum was studied monthly in a littoral population collected from the Gulf of Gabès area. The analysis of oocyte diameter and histological examination of gonads indicates that C. glaucum showed a defined pattern of seasonal gametogenic development. An intense reproductive activity was observed throughout the year, mainly during the autumn and winter seasons. Spawning occurred most of the year, without prolonged periods of reproductive inactivity. Histological observations showed strong interindividual variations of gonad maturity stages over the same sampling period. The study also revealed spawning asynchrony in this species and the presence of various stages of maturity within the same individual. This strategy allows for a semicontinuous production of larvae in a way that some of the larvae will encounter favorable environmental condition over time, which favors their subsequent development. The current study also reveals an occasional manifestation of hermaphroditism.