We performed a retrospective study of patients with systemic lupus erythematosus (SLE) admitted to hospital during a one-year period to describe characteristics associated with a poor outcome. There were 348 episodes of hospitalization of 223 individuals. The cause of admission was clinical flare of SLE (58%), infection (37%) and thromboembolic disease (8%). Readmission occurred in 35.8% and was associated with: active nephritis (HR 2.53, P < 0.01), flare of lupus (HR 2.0, P < 0.01) and more ACR criteria (HR 1.34 per extra criteria, P < 0.01). Individuals with multiple reasons for admission had a longer duration of stay [one = four days (2, 6), two = five days (3, 7) and three = 9.5 days (6.5, 14.5), P < 0.01]. There were 11 deaths (3.2% of admissions). The deaths were due to infection in nine cases (four with concurrent active SLE). In multivariate modelling, the main predictors of death were: previous multiple admissions (OR 12.4, P < 0.01), the presence of infection (OR 7.3, P < 0.01) and younger age (OR 0.93 per increase of one year, P = 0.03). The presence of active lupus nephritis and multisystem disease makes readmission more likely and individuals with multiple problems at the time of admission have longer hospital stays. Young patients with frequent readmissions and coexistent infections are most likely to die.