At Matsumoto National Hospital, 169 patients with prostate cancer were diagnosed between April 1986 and May 1994. The prostate cancer incidence was the highest in the latter half of the seventies, with an average age of 74.3 years. The clinical stage was defined as A1, A2, B, C, and D2 in 24 (14.2%), 38 (22.5%), 39 (23.1%), 23 (13.6%) and 45 (26.6%) patients, respectively. The clinical stage was not correlated with the patient's age. Incidental carcinoma was discovered in 5.8% of the patients who underwent prostatectomy for benign prostatic hypertrophy (BPH). At initial diagnosis, the tumor was well, moderately, and poorly differentiated adenocarcinoma in 71 (42.0%), 64 (37.9%), and 34 (20.1%) patients, respectively. The median follow-up period was 38.7 months. The over all five-year crude survival rate was 54.8%, while the cause-specific five-year survival rate was 80.0%. The five-year crude survival rate was 58.4, 82.0, 55.2, 42.5 and 37.4%, for patients with cancer at stage A1, A2, B, C, and D. The survival rate was higher for patients with cancer at clinical stage A and shorter for those with cancer at clinical stage D than in other stages. Prognosis was also worse in patients with moderately or poorly differentiated adenocarcinoma than in those with well-differentiated adenocarcinoma. The clinical stage and the pathological grade are important as prognostic factors, although the high incidence of death from other diseases shows that the patients' age should be considered to choose the modality of therapy. These findings indicate that intensive treatment of the patients in clinical stage A2, B and C prostate cancer in combination with screening for the men between 50 and 75 years old for early cancer detection is required.