The objective of this study was to determine the sensitivity of tartrate-resistant acid phosphatase (Bone TRAP-5b) for early detection of bone metastases (BM) and to investigate the efficacy of bisphosphonates (BF) (zolendronic acid-ZA) in prevention of bone metastases in patients with Renal Cell Carcinoma (RCC). The 60 patients with RCC with proven BM were investigated to assess the sensitivity and specificity of Bone TRAP-5b. 95 patients with RCC with high level of tartrate-resistant acid phosphatase (Bone TRAP-5b) (8,5±0,2 IU/L) after radical surgical treatment were divided into two groups: 1-st group: (n=44) received zolendronic acid (ZA) (BF +), and 2-nd group (n=51) patients didn't receive ZA (BF-). Patients of both subgroups were similar by age, sex, stage of disease. The levels of Bone TRAP-5b, Ca++, alkaline phosphatase, LDG were accessed every 3 months, and MRI imaging, bone scan with 99mTc every 6 month in both groups. We determined the high correlation between bone TRAP-5b and the presence of bone metastases (r=0,9; p <0,05), but its level wasn't dependent with the number of BM. The results showed the high sensitivity and specificity of Bone TRAP-5b at the critical value of 5.2 IU/L (98,3 % and 90,0 %), (χ2=64,6; p<0.01). Using BF for the prevention of bone metastases in high risk group patients with RCC provides a significant difference in the incidence of bone metastases in patients.