© 2021, The Author(s).Background: The early detection of bone metastases is very important in prostate cancer follow-up. This study aimed to compare conventional tumor markers, namely free prostate-specific antigen (free PSA), total prostate-specific antigen (total PSA), free PSA/total PSA ratio, alkaline phosphatase (ALP) values, Gleason scores and 99 m Tc-MDP bone scintigraphy findings in the prediction of bone metastases in prostate cancer. Methods: In total, 175 patients with prostate cancer who underwent whole-body bone scintigraphy were included in the study. All selected scintigraphic studies were reprocessed. Free PSA, total PSA, free PSA/total PSA ratio, alkaline phosphatase (ALP) values and Gleason scores of patients were recorded. Results: The results of our study show that the presence of bone metastasis correlates very weakly with free PSA/total PSA ratio (rho = 0.179), weakly with total PSA (rho = 0.318) and Gleason score (rho = 0.382), moderately with ALP (rho = 0.539), free PSA (0.416). Only ALP variable had a diagnostic value and ALP cutoff value was 76.50 IU/L, with 80% sensitivity and 82.1% specificity. Conclusion: According to the results of our study; the free PSA, total PSA, free PSA/total PSA ratio and Gleason score values were not considered as a reliable parameter in the prostate cancer cases follow-up for bone metastasis development. Only ALP had a diagnostic value and ALP cutoff value was 76.50 IU / L with 80% sensitivity and 82.1% specificity in predicting bone metastases in prostate cancer.