The possible infections of 43 hospitalized patients with systemic lupus erythematosus (SLE) has been assessed. Out of the 43 patients 17 had some type of infection (41%). The diagnosis was proven by positive cultures in 84% of the cases. Urinary infections due to E. coli were the infections most commonly found. Four infections due to staphylococcus, 2 to S. typhi and 2 to invasive Aspergillosis were also found. Tuberculosis was observed only in 2 patients. In twelve out of the 17 patients with infections, SLE was active and 10 of the latter had renal failure. In addition to the 18 urinary infections diagnosed, sepsis was encountered in 5 patients and pneumonias in 4. Only two infected patients died (those with invasive aspergillosis). Thus, infections are frequent in patients with SLE and precise diagnosis often requires positive culture test.