This study describes the prevalence and cost of hospitalizations due to angina in the United States.. METHOD: Using the 1992 Health Care Utilization (HCUP) database, patients admitted with the principle diagnosis of angina (ICD-9 codes 411.1, 413.1, 413.9) were identified. Results were analyzed based on demographic distribution, procedures performed, mean length of stay (LOS), and total charges. RESULTS: The overall prevalence of hospitalizations due to angina was 2.6%. The highest angina hospitalization rates were among patients between the ages of 55-75 years (5.6%), male (3.4%), and white (3.1%). The most common type of diagnosis was unstable angina (79%), followed by stable angina (19.8%). More than half (55%) of admissions were through the emergency room (ER), and 7.3 % were routine admissions. The most common procedures were removal of coronary artery obstruction (ICD-9 code 36), followed by other operations on heart and pericardium (ICD-9 code 37). The mean LOS and total charges were 4.87 days and $12134, respectively. Mean LOS and total charges per admission varied significantly according to admission source: 4.6, 5.0, 6.9 days and $9130, $15120, $24090 for ER admission, routine admission, and others (e.g. hospital transfer), respectively. Since HCUP represents a 20% sample of total US hospitalizations, total annual charges for hospitalizations due to angina are approximately $10 billion, and the majority of that ($8.7 billion) is due to unstable angina. CONCLUSION: Hospitalization due to unstable angina is the major cost component of the total cost of hospital care for angina in the United States.