OBJECTIVES: To examine patterns of use of drugs for the treatment of chronic heart failure (CHF) and how these patterns change over time. METHODS: We identified a national cohort of patients with CHF in the Department of Veterans Affairs (VA) beginning October 1, 1998 (FY99) and obtained their outpatient pharmacy prescription fill records for FY99 through FY02. We tabulated the proportion of patients receiving filled prescriptions for several categories of drugs across years. To adjust for severity of illness and distinguish birth cohort effects from real changes in practice, patients were stratified based on number of years in the cohort. We then compared patterns of use between groups over time. RESULTS: The total number of patients ranged from 222,288 in FY99 to 301,485 in FY02. The average age(sd) ranged from 69.7(10.3) to 71.1(10.4). The most prevalent categories in FY99 were angiotensin-converting enzyme (ACE) or angiotensin II inhibitors (65.6%), loop diuretics (64.2%), digitalis glycosides (40.3%), calcium channel blockers (CCB, 37.0%), beta blockers (37.1%) and statins (36.3%). By FY02, digitalis and CCBs decreased to 34.0% and 32.4%, while beta blockers and statins increased to 54.0% and 51.8%, respectively. ACE or angiotensin II inhibitor and loop diuretic use remained relatively constant (69.3% and 62.3%, respectively). Among newly diagnosed patients, 40.6% in FY99 received beta blockers; in FY02, 58.8% were started on beta blockers. Of survivors from FY99, beta blocker use increased to 52.7% by FY02, indicating that 29.8% of surviving patients were added to beta blockers and/or survived longer than patients who were not started on that drug class. Similar patterns were observed within other groups. CONCLUSIONS: Pharmacotherapy patterns in the VA changed for patients with CHF from 1999 to 2002, as new evidence emerged from clinical trials. Future work will link these changes in process of care to survival, utilization and cost.