The affinity and diversity of polychaetous annelids in the mangrove habitats of Malaysia, Thailand (Phuket), Japan (Okinawa), Australia, China, Taiwan, South Africa, Hawali and India (Sunderbans, Bombay and Cochin) have been discussed this paper. The study revealed a similarity in the polychaetes of Malaysia, Phuket, Sunderbans and Cochin. The members of the family Nereidae, Eunicidae dominated the mangrove habitat. Marphysa gravelyi, Nereis, glandicincta, Eunice tubifex, Eunicesp., Branchiourpitella singularis and Pista indica were found at Cochin, though hitherto not reported from Malaysian, Phuket and Sunderbans mangrove habitats. The members of the genera Dendronereis, Marphysa and Lumbriconereis are found to be typical mangrove polychaetous annelids throughout the Indo-Pacific region. It is interesting to note that, in general, the errantia polychaete group was more dominant than the sedentaria. The latitudinal difference may be factor in the diversity of species while the physiological adaptation and long standing inter-relationship among various elements seems to be a controlling factor.