Summary— A comparative study of transurethral (TUR) and open prostatectomy for the large prostate gland has been carried out. Over a 5-year period 94 transurethral resections and 73 open procedures were performed for prostate glands weighing more than 50 g. There was a single death in each group, giving relative mortality rates of 1.1% TUR and 1.4% open. The post-operative hospital stay was significantly shorter in the TUR group. The open group suffered significantly more complications in the first week but the TUR patients, although having fewer immediate postoperative complications, had significantly more in the first year, so that overall complication rates were similar (35% vs 36%). Patient satisfaction was equal in both groups.