We report a 73-year-old man with hepatocellular cell carcinoma who had eruptions on and severe pain in the lower leg. Within several hours, the patient's skin lesions had progressed markedly. Magnetic resonance imaging findings were consistent with necrotizing fasciitis. Klebsiella oxytoca was isolated from cultures of biopsy samples taken from the leg. The resulting DNA fingerprint pattern revealed that the enteric bacterium was the same as that obtained from the biopsy samples taken from the leg. Furthermore, a dendrogram showed that genetic proximity between samples was extremely high. These results confirmed that translocation of Klebsiella oxytoca as an enteric pathogen caused the necrotizing fasciitis in this patient.