Objective To determine the incidence of infections in a population of systemic lupus erythematosus individuals and the characteristics of infections regarding original site, as well as to study the possible associations between infections and treatment.Methods An analytical retrospective study using data from medical charts of systemic lupus erythematosus patients from a single university hospital. A total of 144 patients followed up for five years were included. Data collected comprised age of patients and age at onset of lupus, sex and ethnicity, disease duration before the study period, medications, cumulative dose of prednisone, occurrence of infections and their original site.Results The most frequent infections were urinary tract infections (correlated to use of prednisone − p<0.0001 and cyclophosphamide − p=0.045), upper airways infections (correlated to use of prednisone − p=0.0004, mycophenolate mofetil − p=0.0005, and cyclosporine − p=0.025), and pneumonia (associated to prednisone − p=0.017).Conclusion Prednisone was the drug more often associated with presence of infections, pointing to the need for a more judicious management of this drug.