Urethral and penile tissues and their neoplasms are considered anatomically and pathogenetically different. Since we observed urethral dysplastic lesions and some similarities between noninvasive and invasive lesions of the anterior urethra and glans, we designed this study to document epithelial urethral abnormalities in patients with penile squamous cell carcinoma. We examined urethral epithelia from 170 penectomies with invasive squamous cell carcinoma finding a variety of primary epithelial abnormalities in 89 cases (52%) and secondary invasion of penile carcinoma to urethra in 42 cases (25%). Patients' average age was 68 years. Primary tumors measured 4 cm in average diameter and the majority were squamous cell carcinoma of the usual (67%) or verrucous type (15%). Primary epithelial abnormalities found were squamous intraepithelial lesions, metaplasias and microglandular hyperplasias. Urethral squamous intraepithelial lesions of high grade was found in six patients and of low grade in eight cases. Squamous metaplasia, seen in 69 cases, was the most frequent finding. Metaplasias were classified as nonkeratinizing and keratinizing. Nonkeratinizing metaplasias (57 cases) were variegated in morphology: simplex (26 cases), hyperplastic (12 cases), clear cell (11 cases) and spindle (8 cases). Keratinizing metaplasias (12 cases) showed hyperkeratosis and were more frequently associated with verrucous than nonverrucous penile squamous cell carcinoma. Microglandular hyperplasia was present in eight cases. Lichen sclerosus was associated with simplex squamous metaplasia in four cases. Despite the large size of the primary tumors, direct urethral invasion by penile carcinoma was present in only 25% of the cases. The presence of precancerous lesions in urethra of patients with penile carcinoma indicates urethral participation in the pathogenesis of penile cancer. Simplex squamous metaplasia is a common finding probably related to chronic inflammation. Keratinizing and hyperplastic squamous metaplasias may be important in the pathogenesis of special types of penile carcinomas such as verrucous carcinoma.