Background: Providing effective pharmaceutical care to ambulatory care patientswith chronic diseases presents an enormous challenge. Medication therapy management (MTM) is defined as the direct, responsible provision of medicationrelated care for the purpose of achieving definite outcomes that improve a patients quality of life. MTM is a patient-centred service, typically provided by clinical pharmacists in collaboration with physicians and other healthcare providers, that seeks to improve the quality of medication use and intended results among patients who are at high risk of having adverse reactions from medications.Methods and Findings: We tested the hypothesis that MTM provides both improved outcomes and cost reduction as determined by differences in the measurable outcomes (lipid levels, tobacco consumption, weight, prescription cost, and average blood pressure values). Patients were given, at random, the opportunity to participate in MTM in a 5-month period. We found there was a significant reduction in blood pressure, glucose, LDL, triglycerides, cholesterol, and cost for patients participating in MTM.Conclusions: MTM may improve pharmacotherapy outcomes and reduce medication costs.