Thirty patients with necrotizing fasciitis were analyzed. The first 20 patients were reviewed from the patient records of the University of Cincinnati Medical Center (Group A). An additional 10 patients from the University of Cincinnati Medical Center and the Medical University of South Carolina were more recently treated (Group B). The 20 patients in Group A had a mortality rate of 50 percent, whereas no deaths occurred in Group B. The age range and race and sex ratios were essentially identical between the groups. The most common site of infection in both groups was the leg or perirectal-perioneal area. Hemolytic streptococcus, Escherichia coli, and Staphylococcus aureus were the most frequently isolated organisms in Group B patients. The most common organisms isolated from patients in Group A were identical to those found in Group B, with the addition of Bacteriodes. The clinical manifestations in Group A patients were most commonly fever, edema, crepitus, gangrene, cellulitis, and pus in the involved area. In Group B patients clinical signs of fever, crepitus, skin anesthesia, and roentgenographic evidence of gas were the most common clinical manifestations. Ninety percent of patients in Group B were found to have roentgenographic evidence of soft tissue gas. Diabetes and atherosclerotic vascular disease occurred in more than 75 percent of all patients in both groups. Patients in Groups A and B were identical in nutritional status at the time of admission to the hospital. The improvement in the rate of survival in patients in Group B can be attributed to earlier diagnosis and referral, immediate and extensive debridement of all involved tissue, and aggressive protein replacement.