Result of a pre-pollution status survey of the zooplankton of the Vasishta Godavari Estuary (16⁰18´N- 81⁰42´ E) undertaken between October 1981 and June 1983 are presented. Most of the species recorded tolerate much lower salinities than their counterparts of the estuaries in the west coast. Monthly fluctuation of zooplankton showed a distinct major peak in May and one or two minor peaks between October and February in the lower and upper reaches. However, in the middle reaches major peak was seen in November and minor peaks were observed between February and May. Zooplankton of the lower, middle and upper reaches was compared in terms of richness, diversity and evenness of species. Qualitative richness (99 species of adults and 28 types of larvae) and quantitative abundance of zooplankton indicates that the estuary is  highly productive ecosystem, free of any type of pollution affecting its biota