Aspergillus flavus was grown on peanut extract agar and on viable peanut kernels either in pure culture or in dual culture with bacteria isolated from the geocarposphere of roots and pods of field grown peanuts. Aflatoxin production by A. flavus, its growth and interactions with the bacteria were studied at different water activities (aw) and temperatures. Almost all the bacteria (Bacillus megaterium, B. laterosporus, Cellulomonas cartae, Phyllob-acterium rubiacearum Pseudomonas aurofaciens and Xanthomonas maltophila) stimulated growth and aflatoxin production by A. flavus on peanut kernels, especially at 30°C and 0.95 and 0.98 aw. However, F. odoratum showed inhibition of aflatoxin biosynthesis by A. flavus.