The occurrence of mature specimens of Thryssa dussumieri (Val.) in different size groups indicates that the fish matures at 12S-130 mm in total length, which is supported by the results obtained from the study of maturity stages, gonado somatic index and relative condition. Coefficient of regression describes the relationship between the total length of fish and length and breadth of gonads, and between fish weight and gonadial weight. The logarithmic relationship between fecundity and total length, body weight and ovary weight has been established. Frequency distribution of ova suggests that the spawning period is twice i.e. March and August-September in a season. Separate equations for describing length-weight relationship of males and females are justified.