This paper embodies a discussion on the pelagic copepods, especially the calanoids inhabiting, as transitory or permanent residents, the estuaries in India. Out of the 67 species of calanoids recorded from the estuarine waters of India, 36 species occur in the backwaters around Cochin. The occurrence, distribution and seasonal abundance of these species in the estuarine system around Cochin is dealt with. In addition, the influence of the physic-chemical properties of the environment on the spatial and temporal distribution of these species is also discussed.