Background: Acute coronary syndrome (ACS) and venous thromboembolism (VTE) are costly conditions, largely due to the high initial cost of treatment, patient nonadherence to prescribed antiplatelet therapy, avoidable rehospitalization in patients with ACS, and high rate of recurrence and long-term complications in patients with VTE. Objectives: To discuss the economic impact of ACS and VTE; factors that contribute to preventable morbidity, mortality, and costs associated with these conditions; and strategies that managed care pharmacists can use to improve clinician knowledge of evidence-based treatment guidelines and patient adherence to the treatment plan, thereby improving clinical and economic outcomes. Summary: Premature discontinuation of antiplatelet therapy increases the risk of death and rehospitalization in patients with ACS. Factors associated with premature discontinuation include advanced age, lack of education, unmarried status, pre-existing cardiovascular disease, high cost of health care, failure to receive discharge instructions, and lack of referral for cardiac rehabilitation. Managed care plan benefit design should provide for the effective treatment of ACS and VTE by identifying the optimal type and duration of anticoagulant and antiplatelet therapy. In patients with VTE, the use of low-molecular-weight heparin (LMWH) in outpatients is as safe and effective and less costly than standard intravenous unfractionated heparin on an inpatient basis. Long-term LMWH treatment for acute deep vein thrombosis is safe and effective, and it is preferred over warfarin for patients with cancer. Managed care pharmacists can improve the quality of care for patients with ACS and VTE by using a variety of strategies to improve clinician knowledge of evidence-based treatment guidelines and patient adherence to the treatment plan. Conclusions: Efforts by managed care pharmacists to improve the quality of care for patients with ACS and VTE can improve patient outcomes and reduce health care utilization and costs.