During the past 20 years from August 1971 to July 1991, 3215 cases of transurethral resection were performed at Kitasato University Hospital, and consisted of 2008 benign prostatic hyperplasias, 692 bladder tumors, 258 prostate cancers, 167 bladder neck contractures, 38 urethral strictures, 20 chronic prostatities and 32 various urologic diseases. On 2266 transurethral resections of the prostate including 2008 benign prostatic hyperplasias, and 258 prostate cancers analysis was conducted. Patient age ranged from 44 to 97 (mean, 70.1). Resected tissue varied from 1 to 177 (mean, 26.9) grams. The time required for resection was from 9 to 245 (mean, 73.0) minutes. The volume of irrigation fluid was from 4 to 92 (mean, 25.0) liters. The duration of catheter placement after operation was 3 to 44 (mean, 4.1) days and hospitalization, 10 to 81 (mean, 12.1) days. The number of complications and blood transfusions were 308 (13.6%) and 381 (16.8%) respectively. Resected amount of tissue, volume of irrigation fluid, duration of catheter placement and frequency of complication in the benign prostatic hyperplasia group exceeded those in prostate cancer group. The length of hospitalization and blood transfusion rates were higher in the prostate cancer group. The rate or frequency of each item increased with the operating time and amount of resected tissue. Today, 60 minutes of operating time as a limiting factor of transurethral resection is not considered a important factor. Based on the results of the 2266 TURP cases, an attempt will be made to establish safer methods of treatment.