Damsel fishes belonging to the family Pomacentridae constitute one of the major groups of marine ornamental fishes. The present study investigate the gonadal maturation of the Regal demoiselle, Neopomacentrus cyanomos. Samples were collected from southwest coast of Kerala off Vizhinjam. The gonads were examined to determine the maturity stages. The smaller size group up to 65 mm standard length was all females at different stages of maturity. The size at first maturity of females was estimated to be 57 mm standard length.