BACKGROUND Anticoagulation management services (AMSs) are widely used for anticoagulation management in many countries. Our AMS is a pharmacist-run ambulatory clinic with a physician advisory committee that manages patients referred with complicated anticoagulation histories. This paper assesses the adequacy of anticoagulation, rates of anticoagulant-related events and associated health care resource utilization for patients before and after referral to our AMS. METHODS Consecutive patients referred to the AMS with 4 months of prior anticoagulation management who also had anticoagulation management for 4 months within the AMS were included in the evaluation. The primary endpoint was adequacy of anticoagulation (target international normalized ratio [INR] +/- 0.5). Secondary outcomes included adverse events requiring an emergency department (ED) visit or hospital stay. These were classified by International Classification of Diseases (ICD) codes as thromboembolic, hemorrhagic, or non-anticoagulant related. Health care system resource consumption data were collected as number of hours spent in an ED and hospitalization costs. RESULTS A total of 125 patients were included: 57.6% were male, with a mean age of 62.9 (standard deviation [SD]) +/- 15.0 years. Indications for warfarin therapy were atrial fibrillation (40.0%), mechanical valve replacement (24.0%) and venous thromboembolism (19.2%). The adequacy of anticoagulant control was significantly greater during AMS care compared with the period before referral; patients were in the target INR range 66.5% versus 48.8% of the time, respectively (95% confidence interval [CI] 13.4%-22.0%; p < 0.0001). The relative risk of a thromboembolic event before referral to AMS care was 17.6 (95% CI 6.0-51.9; p < 0.0001), while the relative risk of a hemorrhagic event before AMS care was 1.6 (95% CI 0.7-3.7; p = 0.25). During AMS care, savings included 572 hours in the ED and Cdn$122,145.40 in hospitalization costs. CONCLUSIONS A pharmacist-directed, physician-supported AMS program achieved significantly better INR control and reduced rates of thromboembolic complications compared with standard care. Resource utilization was substantially reduced during AMS care.