OBJECTIVES: Prevention or mediation of adverse events can significantly impact a patient’s quality of life and their employer’s healthcare costs.  Decision modeling can be utilized to map pharmacists interventions provided through an employee-sponsored medication therapy management (MTM) program and calculate consequent cost savings associated with improved clinical outcomes. METHODS: A total of 700 employees from 2 employer groups participate in a pharmacist provided MTM program. A team of clinicians and researchers classified and created codes for specific pharmacist interventions, resultant physician and/or patient responses, and consequent outcomes.   Data was extracted from patient charts and entered into Microsoft Excel.  Costs associated with each decision outcome were calculated from claims data. A one-year decision-analytic model was constructed using TreeAge Pro Suite 2008 to identify the cost savings per intervention. RESULTS: A total of 218 interventions were made by the pharmacists.  The most frequently used interventions were “explained and advised the use of pattern management” (N = 95, 43.4%) and “alerted the physician of an abnormal A1c level” (N = 64, 29.2%).  Cost savings resulting from diabetic interventions for ER visits ($71.00 - $337 PPPY), inpatient hospitalization ($460.00 - $2360.00 PPPY), and total costs ($26.00 - $274.00 PPPY). All but one intervention resulted in a loss of cost savings for office visits, indicating that patients visited specialty physicians more often after beginning the program. The total cost savings for these interventions were $165.00 PPPY and $145.00 PPPY, respectively. CONCLUSIONS: This decision-analytic model can be used as a rubric for providers seeking the most effective interventions to utilize for MTM programs, thereby reducing trial-and-error and diminishing health care costs.  The model illustrates the potential return on investment the employer realized as a result of sponsoring employee participation in this program.