Systemic lupus erythematosus developed in a 35-year-old woman who had partial lipodystrophy since she was 7 years old. To our knowledge, this association has been reported only once. She also had hypocomplementemia, mesangiocapillary glomerulonephritis type II, and a serum assay with positive results for C3 nephritic factor. The association of partial lipodystrophy with other autoimmune disorders suggests an immunologic pathogenesis for this disease.