Over the last decade, epidemiological, experimental and clinical studies have implicated oxidative stress in the development and progression of prostate cancer. In the present study, we evaluated the oxidative status and antioxidant defense in patients with prostate cancer (PCa) taking into consideration: treatment, Gleason score and bone metastasis. For this, we measured concentrations of plasmatic thiobarbituric acid reactive substances (TBARS), serum protein carbonylation, whole blood catalase (CAT) and superoxide dismutase (SOD) activities, as well as the plasma and erythrocyte thiol levels and serum vitamin C and E concentration. This study was performed on 55 patients with PCa and 55 healthy men. TBARS levels and serum protein carbonylation were higher in PCa patients than in controls and altered levels of antioxidants were found in these patients. CAT activity was decreased and SOD activity was higher in PCa patients when compared with controls. Non-protein thiol levels were increased, however, serum vitamin C and vitamin E content were reduced in PCa patients when compared with controls. In addition, different parameters analyzed in PCa patients based on metastasis, treatment and Gleason score showed changes in oxidative stress biomarkers and antioxidant defenses. These findings may indicate an imbalance in the oxidant/antioxidant status, supporting the idea that oxidative stress plays a role in PCa, moreover, the oxidative profile appear to be modified by bone metastasis, treatment and Gleason score.