Objective: The objective was to evaluate the relationship between low dose warfarin therapy and hospital utilization. This information will help to evaluate this as a quality of care indicator in elderly patients. Methods: An issue in chronic warfarin therapy is the availability of time and resources necessary to adequately manage patients on anticoagulation therapy. Providers may err on the side of under-dosing due to fears of bleeding episodes. Medicare Part D and A records for 2006 were pulled for all non-ESRD, chronic warfarin users in California, Florida, and Mississippi age 65+. Chronic warfarin users were defined as patients with 3+ warfarin prescriptions covering 180+ days of therapy. Average dose was computed by dividing the total mgs of warfarin dispensed from the first prescription to the next to last prescription and dividing by the number of days between the first and last prescription fills. Low average dose was defined as