Since ethnic differences in the disease expression of systemic lupus erythematosus (SLE) have been recognized, we compared the clinical and serological features in two different ethnic groups of patients with SLE. The study population consisted of 222 African-American and 300 Latin American (Colombian) SLE patients. Clinical, demographic, and laboratory data were obtained by chart review using a standard data collection form. African-American patients more commonly manifested discoid skin lesions, pulmonary fibrosis, and pleuritis, and less commonly manifested photosensitivity, livedo reticularis, and vascular thrombosis than did Latin Americans. In addition, there was a higher frequency of anti-Sm, anti-RNP, and anti-Ro positivity among African-American patients compared with Latin Americans. These results are additional evidence for the presence of ethnic differences in the clinical expression of SLE.