Unfractionated heparin (UFH) and low molecular weight heparins (LMWH) are parenteral anticoagulants commonly used to prevent and treat thromboembolism. These agents are included on the Institute for Safe Medication Practices (ISMP) list of medications that have an increased risk of causing severe patient injury when used in error. Thus the management plan for patients receiving UFH and LMWHs should be thorough and individualized. When constructing an individualized care plan, several factors should be addressed to optimize therapy with UFH and LMWH including the utilization of dosing algorithms for initial and maintenance doses, monitoring laboratory results and adjusting therapy appropriately, providing patient education, and addressing barriers to outpatient use if needed (self-administration techniques, fi nancial burdens, etc). Pharmacists are in the ideal position to address all of these expectations. This chapter outlines the role of the pharmacist in the management of patients on UFH and LMWH.