OBJECTIVES Pulmonary infections and bacteraemia, essentially due to Streptococcus pneumoniae and Haemophilus influenzae, are frequently reported in patients infected with the human immunodeficiency virus (HIV). We retrospectively analyzed episodes of bacteraemia in HIV-infected patients to determine whether supplementary risk factors could be ascertained and whether it would be advisable to propose vaccination. METHODS From June 1986 to February 1992, 41 episodes of bacteraemia in 30 HIV-infected patients were observed in 7 different wards. Data on age, sex, risk group, Centers for Disease Control classification, CD4 counts and clinical outcome were recorded. RESULTS There were 18 males and 12 females, mean age 34 years (range 26-67 years) in CDC class II (n = 11), III (n = 5) and IV (n = 16). There were 17 intravenous drug users (56.6%). There were 8 heterosexuals (26%), 3 homosexuals or bisexuals (n = 3) and 2 patients infected after blood transfusions (6%). All the heterosexual patients were of black-African or Carabean ethnic origin. Mean CD4 count was 239 mm3 (range 2-1148) during the episode of bacteraemia which occurred during an upper respiratory tract infection in 96% of the patients. Recurrent episodes were observed in 7 patients. Outcome of the infectious episode was favourable in 35/41 cases after antibiotic therapy. Six patients (all CDC class IV) died during the episode of bacteraemia. CONCLUSIONS These observations showed that intravenous drug use and black-African ethnic origin are supplementary risk factors for S. pneumoniae infection in HIV-infected patients. The frequency of upper respiratory tract infections in these patients suggests that anti-S. pneumoniae vaccination should be evaluated further.