Objectives - To assess the expression of systemic lupus erythematosus (SLE) in Jewish Israeli patients according to ethnic origin. Methods - Eighty four patients with SLE were divided into groups according to origin and compared for history, physical examination, and laboratory variables. Results - Patients of Sephardic origin had more serious disease manifestations than Ashkenazi patients in 60 of the 76 variables examined. They had significantly worse muscle pain, alopecia, and cutaneous vasculitis, higher antibodies to DNA and erythrocyte sedimentation rate, and significantly lower complement and leucocytes. Sephardic patients were divided into subgroups according to country: Mediterranean area, Iran-Iraq-India, and Yemen. All three subgroups had more serious disease manifestations than the Ashkenazi group, and the Yemenite patients had the most serious manifestations among the Sephardic subgroups. The Sephardic patients had a significantly lower education level, but only origin, and not education level or age, was significantly related to disease manifestations on multivariate analysis. Conclusion - More serious manifestations of SLE are found among Jewish patients of Sephardic origin, but these are not related to level of education or age.