Localized scleroderma has no recognized internal organ involvement but may be disfiguring and disabling when the cutaneous lesions are extensive or affect children. There is no accepted or proven treatment for localized scleroderma. Case reports of 11 patients with severe, extensive localized scleroderma who were treated with D-penicillamine are summarized in this article. This drug was judged to have a favorable effect on the disease course in 7 (64%) of 11 patients. Improvement began within 3 to 6 months and consisted of cessation of active cutaneous lesions in all 7 patients, skin softening in 5, and more normal growth of the affected limb in 2 of 3 children. Joint stiffness and contractures also improved. The dose of D-penicillamine associated with a favorable response was as low as 2 to 5 mg/kg per day given over a period ranging from 15 to 53 months. D-Penicillamine caused nephrotic syndrome in 1 patient and milder reversible proteinuria in 3 other patients; none developed renal insufficiency. These data suggest that D-penicillamine may be effective in severe cases of localized scleroderma.