This study examined the effect of dietary lipids and ovariectomy(OVX) on bone mass in rats. The experimental animals were divided into sham operation(S) or OVX(O) groups and then each group was divided into soybean oil(SS, OS), beef tallow(SB, OB), and fish oil(SF, OF) diet group. Experimental diets were fed for 16 weeks. Weight gain tended to be higher in OVX groups than in sham groups. Weigth gain was the highest in beef tallow group (SB) and the lowest in fish oil group(SF). There were no difference in weight, length, breaking force, strength and circumference of femur mong groups. However, volume of femur tended to be higher in OVX groups than in sham groups. Ash content of femur was significantly lower in OVX than sham groups but there were no difference between SB and OB group. Ca content in the soybean oil and beef tallow group were not influenced by OVX but Ca content in fish oil group was significantly higher in OF than SF group. The SB group showed the hyighest Ca content and the SF group showed the lowest Ca content. P content of femur was significantly lower in OVX groups than in sham groups but there were no difference between SB and OB group. The SS group showed the highest P content and the OS and OF group showed lower P content compare to other groups. From this result, it suggested that beef tallow positively influenced maintenance of bone mass by means of accumulation of body fat in ovariectomy