|Sclerotium rolfsii Sacc. is one of the most important soil borne pathogen of groundnut causing stem rot disease which causes critical crop losses in groundnut growing area. In first part of present research, stem rot pathogen of groundnut, Sclerotium rolfsii, was isolated from the infected groundnut plant part. In later part of research, to search for the effective Bacillus spp. for microbiological control of Sclerotium rolfsii Sacc. 189 Bacillus spp. were isolated from different rhizospheric niches of healthy plants, and primarily screened for in vitro the antagonistic activity against Sclerotium rolfsii, by dual culture technique. Out of these Bacillus spp. RRR6, RRR 15, RRR 16, RRR 18, RRR 19, RRR 20, RRR 26, RRR 29, RRR 30, RRR 31, RRR 33, RRR 34, RRR 36, RRR 37, RRR 38, RRR 39, RRR 40, RRR 41, RRR 53 and RRR 57 found effectively antagonistic against Sclerotium rolfsii, the stem rot pathogen of groundnut in vitro in contrast to other Bacillus spp. During the secondary screening, out of these twenty Bacillus spp., only four Bacillus spp. i.e. Bacillus spp. RRR 15, RRR 16, RRR 36, and RRR 53 found extremely active in controlling the phytopathogen, Sclerotium rolfsii In vitro in dual culture method. These Bacillus spp. RRR 15, RRR 16, RRR 36, and RRR 53 effectively killing the growth of phytopathogen, Sclerotium rolfsii whose percent inhibition was recorded as 87.5, 92.30, 80.55 and 78.37 respectively. These Bacillus spp. was later identified by 16S rRNA sequencing as Bacillus spp. RRR15 as Bacillus amyloliquefaciens RRR15 (MN744706), Bacillus spp. RRR16 as Bacillus amyloliquefaciens RRR16 (MN749517), Bacillus spp. RRR36 as Bacillus mojavensis RRR36 (MN749819) and Bacillus spp. RRR53 as Bacillus mojavensis RRR53 (MN788663) respectively.