Reproductive behaviour inLittorina scabra (Linne 1758) was studied from Porto Novo jetty area and observations were made both in natural habitat and laboratory condition. Copulation was observed throughout the year whenever moisture was abundant. It lasts usually 30–50 min and pairs remain together for several hours after copulation has been completed. Copulation was correlated with lunar phase. Breeding inLittorina scabra was observed throughout the year and spawning occurs during high tide of the newmoon and fullmoon. It is concluded that the breeding cycle completes within two weeks. There is no correlation between the number of offspring and the size of the individual. The first indication of sex cells appear in males and females at the size of 9·02 mm and 8·7 mm respectively. This result indicates that male matures before females. Sex-ratio ofLittorina scabra was 1∶1·44 which showed fluctuation when considered month-wise. Mean shell height of male and female were equal. The development was normal in the salinity ranges of 28–30% and at the temperature of 30°C. The veliger emerged out of the egg at 96 hr after the cleavage has started.