The Molluscans are helpful in purification of water in their capacity to act as scavengers. The Molluscans play an important role in the assessment of water quality that is they are used as Bio indicators. The rivers are always selected as the sites for drinking purposes. The biodiversity of Narmada River is quite varied, rich and needs regular monitoring and conservation as the river is subjected to various sources of point and non point pollution which are posing threat to these biota. The present investigation was carried out in four sampling stations of Narmada River and various species of class Gastropoda and pelecypoda were recorded through out the sampling period. Some species of Molluscans like Lymnea lives in only highly polluted environment. The species like Thiara and Indoplanorbis live in slightly polluted environment, while the species like Pseudomilleria delyi is highly sensitive to pollution and can survive in pollution free environment. On the presence these Species we can know the water quality of river.