Dry seeds of Cyamopsis tetragonoloba (L.)Taub.var. Golden Early-36 and Harit 36 Rani were exposed to 5kR, 10kR and 15kR of gamma rays produced from Co source. Three hundred fifty seeds from each treatment were grown at the experimental farm of Botanical garden of Dr.Babasaheb Ambedkar Marathwada University, Aurangabad. Plant wise and treatment wise capsules were harvested. In the progeny, phenotypically typical plants with regard to chlorophyll development were marked and their frequency recorded. The M3 generation along with respective normal were studied to analyse the mutagenic activity of gamma ray on cluster bean.