Hatchery-reared Penaeus monodon postlarvae were cultured in ponds until they attained adult size. Thereafter, the shrimps were transferred to concrete broodstock tanks for maturation. During the culture period, the morphological changes of the ovary in relation to the development of the external genitalia and other quantitative parameters were examined. Based on histology, primordial germ cell and chromatin nucleolus in the early stages of ovarian development were reported in addition to the stages that have been described earlier on adult specimens, thus completing the description of ovarian development on P. monodon. Females with ovaries at the perinucleolus stage can be impregnated as long as the thelycum is structurally developed to receive the spermatophores. Females with cortical rod stage ovaries either spawned or resorbed their eggs before molting, indicating that the molting cycle overrides reproductive activity in first-maturing females.