We compared the frequency of clinical features of systemic lupus erythematosus (SLE) and determined survival in 113 patients with younger-onset lupus (age ⩾ < at clinical diagnosis) and 25 patients with older-onset disease (age ⩾55 at diagnosis). The most striking difference was in the racial distribution; 59% of the younger patients were black, compared with only 20% of the older-onset patients (P < 0.001). Major manifestations of lupus (including clinically evident renal disease, central nervous system involvement, cutaneous involvement, and hemocytopenia) occurred with similar frequency in both age groups. Antibodies to DNA were detectable equally often in both groups, but hypocomplementemia was more common in the younger patients