During the course of the past twenty-five years, 43 cases of penile carcinoma were seen in the Radiation Therapy Department of Bellevue Hospital. This number for statistical purposes is small but the series is as large as most reported in the English literature and constitutes an addition to the present comparative lack of material on the subject. Incidence While cancer of the penis constitutes but 2 to 5 per cent of all malignant lesions of the skin in males in the United States, the frequency among Hindus and Chinese is 10 and 18 per cent respectively, and the disease accounts for 30 to 40 per cent of all male cancers in the Far East. Cancer of the penis is quite rare among Moslems, who practise ritual circumcision at the age of thirteen, and is practically unknown in Jews, who perform this rite on the eighth postnatal day. Dean, however, cites a case of penile carcinoma in a 66-year old Jew who had cauterization of a venereal lesion at the age of sixteen. The racial and religious distribution in our series was as follows: Age The average age at onset of symptoms was forty-two years, the largest number of cases, 14, occurring in the sixth decade. The youngest patient was twenty-four, the oldest seventy-seven. Table II shows the age grouping. Etiology Melicow et al. in discussing the etiology of penile lesions, note the following “precancerous” conditions: leukoplakia, erythroplasia of Queyrat, Paget's and Bowen's diseases. These authors present an excellent dinco-pathological chart which sets forth the differential diagnostic features of these diseases. There was only one intra-epithelial carcinoma in our series. That phimosis with the retention of smegma plays an important role in the etiology of penile cancer is adequately established by Barney, Dean, and Melicow, who placed the incidence of that condition at 85 per cent, 74 per cent, and 50 per cent respectively. Phimosis or paraphimosis occurred in 52 per cent of our cases. The inspissated smegma is responsible for a mechanical irritation, and the trapped fatty acids produce a chemical change. The early lesions, whether ulcers or nodules, are hidden in the preputial sulcus, and are often erroneously regarded as venereal sores. Such factors account in part for the long delay in procuring proper medical attention, thus maintaining the incidence of early lesions at a deplorably low level. Signs of syphilis, old or coexisting with cancer of the penis, were found by Wickham and Dauvilliers in 80 per cent of 45 cases. This is a considerably higher incidence than that reported in the current American literature, namely, 30 to 40 per cent. Five of our series had a syphilitic history; 13 denied such antecedent disease, but in 7 of these the serologic test for syphilis was positive, bringing the incidence up to 29 per cent. In 12 additional cases there was no history or laboratory evidence of syphilis. Sauer and Leighton state there is a close association between syphilis and carcinoma.