Sixteen of 70 patients with metastatic squamous cell carcinoma (SCC) from the skin had evidence of clinical immunosuppression. In addition to patients with lymphoproliferative disorders or renal failure, those with cicatricial pemphigoid and those undergoing chronic oral corticosteroid therapy were identified as being at high risk. Host immune surveillance appears to play a major role in determining the metastatic potential of cutaneous SCC.