1. Among all tissue examinations, 8.6% were on male urogenital organs, of which 2.9% were for carcinoma of the prostate. Biopsies of the prostate comprised a large percentage of all male urogenital biopsies. Since the specimens examined by various pathological laboratories in Tehran were received from all over the country, comparison of these statistics is significant. 2. Male urogenital tumors comprised 6.7% of male biopsies, of which 2.7% were for tumors of the prostate. 3. Male urogenital cancers comprised 2.3% of biopsies examined, of which only four were prostatic carconomas. Carcinoma of the prostate was the rarest cancer of the male urogenital organs in Iran. 4. We found 933 cases of cancer of male urogenital organs in 31 years. This comprised 6% of all male cancers, of which only 0.33% were carcinoma of the prostate. 5. Bladder carcinomas were the commonest and prostate carcinomas the rarest among males. 6. We found that 97% of prostate tumors were benign and 3% were malignant. Prostatic carcinoma was four times more prevalent among high income patients than among low income patients. 7. Benign tumors were most common in the 40 to 70 age groups, whereas the peak incidence for carcinoma of this organ was 50 to 70 years of age. 8. No particular clinical symptoms were found. Most patients reported pollakiuria, dysuria or urinary retention. 9. The initial growth site of tumors in the few cases that we were able to study was in the cortex region, especially from the posterior lobe. 10. Histological types of tumor found did not differ from other figures reported. We found no sarcomas. 11. No systematic study of asymptomatic nodules of carcinoma of the prostate has been made and we have never found any signs of such solitary nodules. This may be due to the low average age and the rarity of malignancy of the prostate in Iran. 12. The frequency of death in Iran due to carcinoma of the prostate is impossible to state since death certificates, in the majority of cases, specify secondary symptoms of the disease and not the original disease. 13. The incidence of prostatic carcinoma in the provice of Fars was five times greater and in Isfahan four times greater than in the province of Tehran. However, the figures for Tehran were compiled over the last 31 years, whereas the figures for Isfahan and Shiraz are only for the last ten years, and comparison of these three sets of figures may not be accurate. 14. Carcinoma of the prostate is not as common in Iran as it is in Europe and America. It is rather rare in Iran and compares favorably with figures for the Near Eastern and Far Eastern countries. The Middle Eastern countries of Lebanon, Israel and Afghanistan are very similar in incidence to Iran. In other countries in our region, the incidence is 1.8%.