Peanut cultivation in peatlands has major obstacles in terms of controlling plant diseases. One of them is stem rot disease caused by Sclerotium rolfsii Sacc. Organic matter in peat provides nutrients for pathogens as long as there are no hosts. Disease control using pesticides may be effective, but is short term. Besides that, the use of pesticides unwisely can have a negative impact on the environment. biological control can be an option for this pathogen. besides being environmentally friendly, it also has a long-term effect in suppressing pathogens during favorable environmental conditions. The exploration of antagonistic bacteria as a biological control agent for S. rolfsii aims to find local bacteria that have the potential to control of peanut stem rot disease on the peatland of Kuala Pesisir-Nagan Raya. This research was conducted in the Kuala Pesisir sub-district, Nagan Raya District, Aceh, Indonesia. research activities include isolation, morphological identification, pathogenicity testing, antagonistic testing, and molecular identification. The results obtained 67 bacterial colonies from three sources including weed rhizosphere around peanut cultivated, peanut rhizosphere, and peanut roots. Bacterial isolates that have the potential to suppress S. rolfsii were identified as Bacillus sp.