Thirty-two cases of Xanthomonas maltophilia bacteremia have been identified over the last two years at the Veterans General Hospital, Taipei. Among them, 27 cases (84%) were due to hospital-acquired infections, and 14 cases (44%) were polymicrobial bacteremia. One case was confirmed as prosthetic valve endocarditis and one case was complicated by recurrent attacks of ecthyma gangrenosum. Most cases had severe debilitating conditions. Twelve cases (38%) had a malignancy, 19 cases (59%) were resident in the Intensive Care Unit and 16 cases (50%) had undergone major surgery. The main predisposing factors included central venous catheterization, endotracheal intubation or tracheostomy, prior antibiotic therapy and prolonged hospitalization. Moxalactam, chloramphenicol and trimethoprim-sulfamethoxazole were the most effective agents in vitro against X. maltophilia. Twenty-two cases (69%) died during hospitalization; 13 cases (41%) were directly attributed to septicemia. Factors that adversely influenced mortality included inappropriate antimicrobial therapy and prior antibiotic treatment. Of particular interest is the fact that none of the patients who did not receive appropriate antimicrobial therapy survived. Early diagnosis and appropriate antibiotic therapy are critical for improving the prognosis of X. maltophilia infection.