Stenotrophomonas maltophilia is an emerging nosocomial pathogen with a tendency to be resistant to several antibiotics commonly used to treat nosocomial infections. Early recognition of the risk factors for bacteraemia caused by S. maltophilia could potentially improve the prognosis in these cases. Most data have been obtained from a limited number of descriptive studies. In this retrospective case-control study, we investigated the risk factors for S. maltophilia bacteraemia. We compared cases with 2 different control groups; non-bacteraemic patients and those with bacteraemia caused by Escherichia coli. 37 cases were matched with 37 control patients with nosocomial E. coli bacteraemia and 74 non-bacteraemic patients. The demographic information was extracted from the chart of the patients. When the effects of multiple factors were analysed simultaneously, the presence of a central venous catheter and carbapenem use were associated with an increased risk for bacteraemia caused by S. maltophilia compared with both the non-bacteraemic and bacteraemic control groups. We found a mortality rate of 21.6% in cases vs non-bacteraemic controls; however, this was not a statistically significant difference from that observed in patients with E. coli bacteraemia.