The use of methotrexate in psoriasis has recently been questioned because of possible carcinogenic potential. Two hundred twenty-four patients began methotrexate therapy during 1960 to 1965 at the Cleveland Clinic and at Duke University Medical Center. The incidence of malignant neoplasms and mortality has been studied in 205 of these 224 patients. Mortality increased with hepatic disease. No increased incidence of total internal malignancy was found, nor did any one type of neoplasm appear predominant.