OBJECTIVES: Waste in prescribing, dispensing, and consumption of medications in community settings significantly impacts the US Health Care System. This research examines waste associated with the medication use process which consists of any written prescriptions that are not (1) taken to a pharmacy to be filled, (2) taken to be filled but abandoned at the pharmacy, or (3) result in a medication being dispensed but not consumed as directed. The aim of this study is to quantify the costs of medication waste in the United States exclusive of impact on health outcomes. METHODS: A review of published literature and data from the 2012 Medical Expenditure Panel Survey was used to quantify the number of prescriptions wasted at different stages of the medication prescribing and use process. Costs associated with medication waste included physician time and overhead lost writing prescriptions, pharmacist time and overhead lost filling prescriptions, and ingredient costs of medications not used. RESULTS: In 2012, more than 8 million prescriptions were either unfilled or abandoned, and 70 million resulted in dispensed medications that were not used. The total cost of this waste was estimated at more than $14 billion. This result excluded any additional costs associated with not achieving desired health outcomes.   CONCLUSIONS: Patients who do not fulfill their role in the medication use process cause significant, avoidable costs to the health care system beyond the health outcomes not achieved.