There is a wide variation in the natural history of systemic lupus erythematosus (SLE) among different ethnic and geographical groups. Studies in Arabs are few and those in North Africans and especially in the Tunisian population do not exist. This study aims to demonstrate the demographic, clinical and laboratory characteristics of SLE Tunisian patients and to identify those at high risk for renal and neuropsychiatric involvements. One hundred patients with SLE (American College of Rheumatology criteria), seen at the Department of Internal Medicine of the University Hospital La Rabta in Tunisia over a 15-year period (1987 to 2001) were retrospectively enrolled. There were 92 women and eight men with an average age at the onset of disease of 32 years. Nineteen patients were aged over 50 years at the moment of SLE diagnosis (late-onset SLE). Of the patients, 78% had articular involvement, 53% photosensitivity and 63% malar rash. Serositis occurred in 45 patients of whom 16 had pericarditis and 29 had pleuritis. Nephritis was diagnosed in 43% of the cases and consisted always of glomerular nephritis, in three cases of which tubulointerstitial lesions were also observed. Comparison of patients with and without renal involvement showed that lupus nephritis was significantly associated with pericarditis (P = 0.03), arterial blood hypertension (P < 0.0001), cryoglobulinemia (P = 0.07) and antiphospholipid syndrome (P = 0.03). The SLEDAI at SLE diagnosis was significantly higher for lupus nephritis patients. Twelve patients with lupus nephritis died compared with three patients in the remaining group (P < 0.0001). Neuropsychiatric manifestations were observed in 25% of the cases. The mean age at SLE onset was significantly lower, the mean SLEDAI at SLE diagnosis and the mortality were significantly higher in the neuropsychiatric group than in the remaining group. Immunological features included antinuclear antibodies (100%), anti-DNA antibodies (56%), anti-Sm antibodies (61%), anticardiolipin antibodies (62%), anti-beta2GP1 (13%) anti-Rnp (23%) and hypocomplementemia (48%). The frequencies of pulmonary hypertension (25 versus 2%, P < 0.00001) and vascular thrombosis (25 versus 2%, P < 0.00001) were significantly higher in patients with positive anti beta2GP1 antibodies. The five-year survival rate in our series was 86%. The most frequent causes of death were active SLE and infections.