Of 2,141 patients with scleroderma who were seen at the Mayo Clinic, Rochester, Minn, between 1959 and 1975, 78 had 87 internal malignancies. The relative frequency of the types of cancers was similar to that for the general population. The increased numbers of patients with breast and uterine carcinomas were consistent with the female preponderance in scleroderma. Contrary to previous reports, carcinoma of the lung was not the most frequent malignancy associated with scleroderma. The lymphoma-leukemia malignancies were second only to breast carcinoma in frequency, comprising about 17% of the malignancies. Both conditions developed within a three-year period in 68% (45/66) of our patients affected with systemic scleroderma, and this subgroup comprised a high mortality group. This study is not an epidemiologic one in the strictest sense, but it is a review of the experience of the Mayo Clinic with patients who have had both scleroderma and an internal malignancy.