PURPOSE Case series have shown a Fournier's gangrene mortality rate of 20% to 40% with an incidence of as high as 88% in some studies. Because to our knowledge there are no population based data, we used a national database to investigate the epidemiology of Fournier's gangrene. MATERIALS AND METHODS We used the State Inpatient Databases, the largest hospital based database available in the United States, which includes 100% of hospital discharges from participating states. Inpatients diagnosed with Fournier's gangrene (ICD-9 CM 608.83) who underwent genital/perineal débridement or died in the hospital were identified from 13 participating states in 2001 and from 21 in 2004. Population based incidence, regional trends and case fatality rates were estimated. RESULTS We identified 1,641 males and 39 females with Fournier's gangrene. Cases represented less than 0.02% of hospital admissions. The overall incidence was 1.6/100,000 males, which peaked in males who were 50 to 79 years old (3.3/100,000) with the highest rate in the South (1.9/100,000). The overall case fatality rate was 7.5%. Patients with Fournier's gangrene were rarely treated at hospitals (mean +/- SD 0.6 +/- 1.2 per year, median 0, range 0 to 23). Overall 0 to 4 and 5 or greater cases were treated at 66%, 17%, 10%, 4%, 1% and 1% of hospitals, respectively. CONCLUSIONS Patients with Fournier's gangrene are rarely treated at most hospitals. The population based mortality rate of 7.5% was substantially lower than that reported in case series from tertiary care centers.