Purpose : To evaluate effect and tolerance of external beam radiotherapy for carcinoma of the prostate and define the optimal radiotherapeutic regimen. Materials and methods : We retrospectively analyzed the records of 60 patients with prostate cancer who were treated with external beam radiotherapy with curative intent in our institution between September, 1987 and March, 2000. Histologic diagnosis was established by transurethral resection or ultrasonography guided biopsy. The major presenting symptoms were a nodule at routine prostatic examination and frequency and urgency of urination, along with dysuria. The median age was 63 years with range of 51 to 87 years. There were 6 patients in Stage A, 20 in Stage 8, 26 in Stage C, and 8 in Stage Dl. All patients were treated with megavoltage equipment producing 10 MV photons. The 4 field pelvic brick technique was used to a dose of 45 Gy or 50.4 Gy at 1.8 Gy per day in 5 to 6 weeks, after which a small boost field was delivered 2.0 Gy per day to a total dose of 66 to 70 Gy. The follow-up period ranged from 1 to 8 years. Results : Actuarial 5-year and 7-year survival rates for Stage A, B, C, and D1 were $100\%\;and\;84\%$, $83\%\;and\;72\%$, $67\%\;and\;54\%$, and $v$, respectively. The corresponding 5-year and 7-year relapse free survival rates were $84\%\;and\;84\%$, $77\%\;and\;67\%$, $48\%\;and\;40\%$, and $33\%\;and\;25\%$, respectively. Relapse free 5-year survival rates for Stage B were $80\%,\;80\%,\;and\;50\%$ for well, moderately, and poorly differentiated tumors, respectively. These were $64\%,\;44\%,\;and\;33\%$ for Stage C, respectively. The local control rates at 5 years were $84\%,\;85\%,\;78\%,\;and\;60\%$ for Stage A, B, C, and D1, respectively. Mild to moderate complications were observed in $22\%$ of patients. Severe complications requiring surgical procedures were documented in only $3\%$ of patients. Conclusion : This study confirms that external beam irradiation is an effective and safe treatment for prostatic cancer, providing long-term local control and good survival with acceptable complications.