The effects of arbuscular mycorrhizae fungi (AMF) against stem rot disease caused by Sclerotium rolfsii Sacc. in peanut were investigated. The mycorrhizal fungi used were Glomus etunicatum, Glomus mosseae, Glomus clarum, Glomus caledonium, Glomus fasciculatum, Gigaspora margarita. In pot experiments, mycorrhizal fungi decreased infected plant ratio between 17.5 - 84.0%. G. caledonium showed the highest effect by 84.0%. The AMF decreased the disease severity between 37.8 - 64.7%. The effect on disease severity of G. caledonium and G. clarum were 63.3 and 64.7%, respectively. In field trials, the effect on disease locus of mycorrhizal fungi ranged between 30.6 and 47.2%. G. caledonium showed the lowest effect with 30.6% while the other mycorrhizal species had the same effect. G. etunicatum and G. caledonium increased the yield by 24.3%. The results show that AMF fungi could effectively be used against stem rot caused by S. rolfsii.