The clinical and serologic characteristics of 199 systemic lupus erythematosus patients with early and late onset of disease were compared to determine if the disease in the older age group defines a specific subset of SLE. This study demonstrated that SLE in the elderly patients exhibits peculiar clinical features with a high frequency of muscular involvement (p < 0.05) and low frequency of cutaneous manifestations (p < 0.001) and alopecia (p < 0.02). Moreover, the most frequent clinical manifestation was muscular pain and stiffness, arthritis and weight loss (over 10 kg). This condition is often hard to distinguish from polymyalgia rheumatica or underlying malignancy. The frequency of autoantibodies was similar in both groups. The absence of anti-La was surprising, however it was confirmed by "Western blotting". The symptoms of late onset SLE are not very prominent however the diagnosis should be considered in order to avoid delays in treatment.