Serratia plymuthica is an uncommon cause of human infection. Only one case of chronic osteomyelitis and two cases of sepsis secondary to central venous catheter infection have been documented. We report the isolation of S. plymuthica from six patients. The organism was recovered from blood cultures in three cases in which the patients had lymphoblastic leukemia, lymphoma, or stroke. Two isolates were recovered from exudates (following knee and abdominal surgery). In the last case, the organism was isolated from the peritoneal fluid of a patient with cholecystitis. The infection was considered nosocomial in five cases and community acquired in the other.