Abstract: Bat guano is known to contain all the macro and micronutrients that plants require in a natural form and hence ably serve as plant fertilizer, soil builder, soil cleanser, fungicide, nematocide and compost activator. In ancient times it was used in agricultural practice as manure but with advent of chemical fertilizers its usage became less popular. Health menace created by chemical fertilizers is again polpularizing organic farming but bat guano is still not popular among the farming community since no explicit work on its plant growth promoting activity has been done. Hence the present study was undertaken to study the effect on the growth of Vigna radiata seedlings using Megaderma lyra guano from two different geographical locations (Yennehole and Varanga) in different quantities (soil: guano; 20:1, 20:0.5, 20:0.1) and in two types of soil (Autoclaved and Nonautoclaved).NPK content of guano was also analysed using standard techniques. The results clearly indicated that the M lyra guano was rich in Phosphorus content and comparing the guano from two locations the Varanga guano was found to be higher in its nitrogen content. Plant growth assay indicated that guano from Yennehole was found to be better as manure compared to that from Varanga. Likewise bat guano was required in a very small quantity to increase the efficiency of plant growth. Amendment of both types of soil with bat guano from both locations showed good growth at soil: guano ratio of 20:0.5.