OBJECTIVE: To determine the impact of acute rheumatic fever (ARF) and chronic rheumatic heart disease (CRHD) on hospital expenditure in the United States. METHODS: This study analyzed data from the Healthcare Cost and Utilization Project (2000) funded by the Agency for Healthcare Research and Quality. Hospitalizations due to ARF and CRHD were identified using ICD-9 codes 390-398 as principal diagnoses. RESULTS: In 2000, there were approximately 1,226 and 44,659 hospitalizations due to ARF and CRHD, respectively. Females accounted for about 58% of all hospitalizations due to ARF, and 63% due to CRHD. The elderly aged 65 years and older accounted for 74% of the hospitalizations due to CRHD, followed by adults aged 35-64 years (24%). The two most common comorbid conditions associated with CRHD were atrial fibrillation (49%) and hypertension (34%). The two most common procedures performed during CRHD hospitalizations were extracorporeal circulation for open heart surgery (10%) and diagnostic ultrasound of the heart (7%). The mean (and median) length of hospital stay for ARF and CRHD was 7.5 (5) and 7.9 (6) days, respectively. Average charge per hospital stay was about $29,500 for ARF and $38,700 for CRHD. Total annual hospitalization charges for ARF and CRHD were estimated at $1.9 billion in year 2002 US dollars. CONCLUSIONS: Rheumatic fever and its sequelae CRHD represent a significant economic burden in the US. Total annual hospitalization charges estimated for ARF and CRHD are substantially higher than the recent estimate by the Institute of Medicine (Vaccines for the 21st Century, A Tool for Decisionmaking, 2000) for all group A streptococcus-associated hospitalizations (