Abstract.Reproductive parameters of the females ofPenaeus semisulcatusregarding the process of ovary maturation, the degree of synchronization of the ova maturation stage within an ovary, the correlation between female length and both maturity and fecundity, as well as the relationship between moulting, copulation and ovarian maturity stage were investigated.The seasonal and spatial pattern of the reproduction of the female population ofP. semisulcatusalong the southeastern coast of the Mediterranean was determined.Average ova diameter, morphological appearance of the ova, presence of sperm, characteristics of the spermatophore, and hardness of the cuticle were used in order to study the above parameters.