Reports from case series have estimated the incidence of peripartum cardiomyopathy (PC) at 1 case/1,485 live births to 1 case/15,000 live births and probable mortality rates of 7% to 60%. The objective of this study was to produce the first population-based study of the incidence, mortality, and risk factors for PC. The National Hospital Discharge Survey was used. Discharge information was available for 3.6 million patient discharges from 1990 to 2002. There were an estimated 16,296 cases of PC from 1990 to 2002. During this period, there were 51,966,560 live births in the United States. Thus, the incidence of PC was 1 case/3,189 live births. There was a trend toward an increase in PC incidence during the study period, with an estimate for the years 2000 to 2002 of 1 case/2,289 live births. The in-hospital mortality rate was 1.36% (95% confidence interval 0% to 10.2%). The total mortality rate was 2.05% (95% confidence interval 0.29% to 10.8%). Patients with PC were older (mean age 29.7 vs 26.9 years), were more likely to be black (32.2% vs 15.7%), and had a higher incidence of pregnancy associated hypertensive disorders (22.5% vs 5.87%) compared with national data. In conclusion, the incidence of PC is relatively uncommon, occurring at an average frequency of 1 case/3,189 live births from 1990 to 2002. The estimated mortality of 1.36% to 2.05% (95% confidence interval 0.29% to 10.8%) is less than previously reported from most case series.