Studies on root diseases and causal fungi on soybean in Indonesia were carried out. Missing plants due to damping-off of seedlings occurred frequently. In addition, the average infection rates of root rots amounted to 60% of all the surviving plants toward the pod filling stage. The more severe root rot was, the lower the yield of soybean seeds. The isolates from the seedlings showing damping-off belonged mainly to either Pythium apanidermatum, Sclerotium rolfsii, anastomosis groups (AG) 4 and 7 of Rhizoctonia solani, AG-E and other AGs of binucleate Rhizoctonia spp. As time went on, the severity of the root rot symptoms increased rapidly and Fusarium spp. and binucleate Rhizoctonia were predominantly isolated from rotten roots in the great majority of the fields, except for one field where root rot disease caused by Cylindrocladium sp. occurred. All the isolates of S. rolfsii, R. solani AG-4 and AG-7, binucleate Rhizoctonia AG-E, P. aphanidermatum, P. myliotylum and Pythium sp. caused damping-off as well as root rot on soybean, whereas the isolates of F. solani and C. floridanum from soybean were pathogenic to the plants in the middle or late stage of growth. A new root rot disease caused by C. floridanum and damping-off disease caused by AG-7 and AG-E of Rhizoctonia spp. were detected for the first time in soybean fields in Indonesia.