The purpose of the study is to investigate the effect of sex and season on reproduction of Gilthead seabream (Sparus aurata). A total of 88 sexually mature S. aurata fish were collected from natural habitat, Manzalah lake Damietta, Egypt during the period from March, 2017 to September, 2018. Fish were maintained in aquaria for 24h at appropriate environment according to each season. The results of the study showed high condition factor in male, females and hermaphrodites in winter. Gonadosomatic index (GSI) recorded high value in hermaphrodite in winter and hepatosomatic index (HSI) was high in females in winter. The absolute fecundity was higher in autumn than winter while the egg diameter was higher in winter than autumn. It could be concluded that, spawning was prevalent during winter season and triggered by lower water temperatures.