Annandale (1915) was the first to record Orcaella brevirostris from Chilka Lake in large numbers and gave a detailed report on its habits and behaviour. The present account is a comparative study with that of Annandale's, based on the recent survey conducted by the Zoological Survey of India from 1985 to 1987. It is found that the number of Irrawady River dolphins has dwindled so much that its sighting in Chilka Lake is rare and only a trained eye can spot the animal, when it takes to surface for a shortwhile for breathing. The factors which could have caused the depletion of this species are discussed. It is recommended that O. brevirostris be declared as an endangered species in this part of the subcontinent to enable conservation.