Pseudomonas putida was recovered from blood culture specimens between 1980 and 1985 in 15 patients with cancer. No isolates were found in specimens obtained before 1980. Eight patients were considered to have septicemia (more than one positive blood culture result plus clinical signs of infection). Septicemia was monomicrobial in three of those eight patients and polymicrobial in five. Of these eight patients, one had pneumonia and three had phlebitis, cellulitis, or both at the site of the venous catheter. The infection appeared to be catheter-related in these three patients, with response to catheter removal in one patient, response to catheter removal and antibiotics in one patient, and response to antibiotics alone in one patient. P. putida was isolated from the site of insertion and the tip of the catheter in one of these three patients. Following therapy, all patients had a rapid recovery from their infection. In vitro susceptibility testing revealed that 90 percent of the isolates were susceptible to piperacillin, ceftazidime, imipenem, and ciprofloxacin.