Of 495 patients definitively irradiated for prostatic carcinoma, 286 with a minimum follow-up of thirty-six months were studied. While tumor histology appeared to predict prognosis, the poorly differentiated tumors showing the highest incidence of distant metastasis and the lowest survival, local tumor control was an important factor within the poorly differentiated group. Of those with local recurrence, distant metastases developed in 68 per cent compared with 37 per cent of those with no local disease (p = 0.025). Survival was similarly affected with 86 per cent of those with locally controlled tumor who were alive at five years (not significantly different from the more well-differentiated tumors) versus a 56 per cent actuarial survival in those with locally recurrent disease (p less than 0.05).