This study was conducted to examine the effects of recombinant Bovine Somatotropin (rBST), vitamin E(Vit. E) and selenium (Se) administration on the blood chemical values and hormone concentrations of serum in Hanwoo sires. Hanwoo sires were randomly assigned to five groups; 1) control, 2) rBST,0.09mg/kg body weight (BW), 3) Vit E, 1,500IU/kg BW, 4) Se 0.1mg/kg BW, 5) Vit E, 1,500IU plus Se 0.1mg/kg BW. rBST, Vit. E and Se for each experimental group were given 6 times at 15 days interval by intermuscular injection. Blood samples were collected ten times for experimental periods and separated the serum by centrifugation and stored into deep freezer. The concentration of albumin was the highest in Se group than those of any other groups (P＜0.05) and Vit. E plus Se group was significantly higher than in the control and rBST groups (P＜0.05). The concentrations of blood urea nitrogen (BUN) and creatinine were significantly higher in rBST group than any other groups (P＜0.05). The concentration of total protein in rBST, Se and Vit. E plus Se groups were significantly higher than in control group (P＜0.05). The concentrations of calcium, cholesterol,, glucose, inorganic phosphorus and triglycerides in serum were not difference in all experimental groups (P＞0.05). The concentration of estradiol was slightly higher in Se and Vit. E plus Se groups than those of any other groups, but not significantly difference among the experimental groups (P＜0.05). The concentration of testosterone was not affected by the administration of rBST, Vit. E and Se.