Studies on diversity among thirty six genetically diversified genotypes of blackgram (Vigna mungo (L.) Hepper) under rice fallow situation for ten quantitative characters, revealed that the genotypes of diverse origin were grouped into seven different clusters. Cluster I & cluster II consisted of twelve genotypes followed by cluster IV consist of five genotypes, clusters III consist of four genotypes and cluster V, VI & VII consist of one genotypes. The highest intra cluster distance for yield traits were found in cluster IV followed by cluster III, clusters I and cluster II. The maximum inter cluster distance (D2-values) was found between cluster III and VII followed by cluster V & VII, cluster I & cluster VII, cluster IV & cluster VII and cluster VI & cluster VII. The clustering pattern revealed that the genotypes originating from different geographical regions got themselves grouped into different clusters. This indicated that the geographic biodiversity is not the only factor in determining genetic biodiversity, the factors other than geographical diversity might have been responsible for grouping of genetic divergence. Grain yield per plot showed high contribution toward total divergence followed by 100 seed weight, number of branches, plant height and days to 50% flowering. However, the bio-divergent genotypes viz., LBG 787, VBG 4-4, IPU 2-43, LBG 623, KKB 05011, TGBG 26, TU 94-2, WBG 108, PU 40, TGBG 401 and LBG 648 were found promising by the studies of Mahalanobis D2 analysis and Tocher's method of clustering and may serve as potential parental genotypes for future hybridization programme.