87 Background: The adverse events of androgen deprivation therapy (ADT) are widely recognized, but ADT-induced alterations in lipid and glucose metabolism may be race-dependent. We prospectively recruited Japanese patients with newly diagnosed prostate cancer who underwent at least one year of ADT and examined changes in lipid and glucose metabolism in these patients. Methods: Patients with newly diagnosed prostate cancer were recruited between January 2011 and August 2012. Body weight, abdominal circumference, and blood testing results were recorded every three months, and visceral and subcutaneous fat were measured by computed tomography before and after one year of ADT. Results: One hundred three patients completed a one year course of ADT. Median age was 74 (range, 50 to 85). Thirty nine patients underwent ADT with luteinizing hormone-releasing hormone (LHRH) agonist monotherapy, while 64 patients underwent ADT with LH-RH agonist plus bicalutamide. Median prostate-specific antigen (PSA) before ADT was 16.7 ng/ml (range, 3.6-3316 ng/ml). Clinical stage was B (46.6%), C (28.2%), and D (25.2%). Mean increase in body weight, abdominal circumference and body mass index after one year of ADT was 3.8%, 4.1%, and 3.8%, respectively. Mean decrease of hemoglobin was 5.5%. Mean increase of total, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol and triglycerides was 9.0%, 10.8%, 5.0%, and 21.0%, respectively. Mean increase in fasting blood sugar and HbA1c was 4.6% and 1.7%, respectively. Changes in each variable from baseline to 0, 3, 6, 9, and 12 months was as follows: body weight, 0, 0.9, 2.7, 3.3, and 3.8%; hemoglobin, 0, 4.5, 3.7, 5.5, and 5.5%; total cholesterol, 0, 12.9, 11.4, 9.7, and 9.0%; triglycerides, 18, 26, 25, 21%; and HbA1c, 0, 2.1, 1.2, 1.2, and 1.7%. Increase of visceral and subcutaneous fat measured by computed tomography before and after one year of ADT was 32.4% and 35.4%, respectively. Conclusions: One year of ADT caused significant changes, especially in lipid metabolism, in Japanese patients with prostate cancer. Visceral and subcutaneous fat increased more than 30%. These changes were noticeable in the first half of the one year course of ADT. Appropriate monitoring and management of these patients is needed, because these changes might cause critical cardiovascular events. Clinical trial information: UMIN000004709.