During the course of a review of 520 patients with systemic lupus erythematosus (SLE) two unusual families were observed. In one, dermatomyositis occurred in the daughter of a patient with lupus erythematosus; in the other, poikiloderma vasculare athrophicans appeared in the identical twin sister of a patient with SLE. The purpose of this report is to present these cases, suggest that they may be variants of SLE and to review the familial incidence of rheumatic disorders in a series of 520 cases of SLE.