The effects of cheonggukjang and doenjang on bone mineral density, trabecular area and cortical thickness of the tibia, and serum osteocalcin level in ovariectomized rats were investigated. After 4 weeks, bone mineral density, bone trabecular area, the cortical thickness index, and serum osteocalcin level were analyzed. The cheonggukjang and doenjang diet groups showed significant prevention of ovariectomized (OVX)-related body weight gain. Whole body bone mineral density of the OVX group was significantly lower than that of the sham group, whereas the cheonggulgang and doenjang diets resulted in complete restoration of bone mineral density. Trabecular area in the proximal diaphysis and cortical thickness in the distal diaphysis of the tibia were increased significantly in the cheonggukjang and doenjang diet fed groups. The cheonggukjang and doenjang diets significantly reduced serum osteocalcin level in the OVX rats. These results suggest that cheonggukjang and doenjang might have inhibitory effects on osteoporosis, by showing accelerated bone formation in OVX rats.