The presence of immunoreactive epidermal growth factor receptors in human skin tumors was investigated using the indirect immunoperoxidase technique. Sixteen basal cell carcinomas and 11 squamous cell carcinomas were evaluated. All of the specimens studied were receptor positive. In 70% of the specimens there was prominent staining of the cell membranes. In 54% of the nodular basal cell carcinoma specimens there was increased staining at the periphery of the tumor cell masses.