Although chest pain centers are promoted as improving emergency cardiac care, no data exist on their structure and processes. This national study determines the 1995 prevalence rate for emergency department (ED)-based chest pain centers in the United States and compares organizational differences of EDs with and without such centers. A mail survey was directed to 476 EDs randomly selected from the American Hospital Association's database of metropolitan hospitals (n = 2,309); the response rate was 63%. The prevalence of chest pain centers was 22.5% (95% confidence interval 18% to 27%), which yielded a projection of 520 centers in the United States in 1995. EDs with centers had higher overall patient volumes, greater use of high-technology testing, lower treatment times for thrombolytic therapy, and more advertising (all p <0.05). Hospitals with centers had greater market competition and more beds per annual admissions, cardiac catheterization, and open heart surgery capability (all p <0.05). Logistic regression identified open heart surgery, high-admission volumes, and nonprofit status as independent predictors of hospitals having chest pain centers. Thus, chest pain centers have a moderate prevalence, offer more services and marketing efforts than standard EDs, and tend to be hosted by large nonprofit hospitals.