OBJECTIVES: Determine if Medicare Part D beneficiaries who received telephone MTM services had:1) Decreased medication/health-related problems (MHRPs); 2) Improved medication adherence; and 3) Decreased total Part D drug costs when compared to a control group. METHODS: Part D beneficiaries from a Texas health plan participated. The Andersen Model was the theoretical framework. Independent variables were: predisposing factors (age, gender, and race); and need factors (number of medications and chronic diseases and medication regimen complexity (MRC). The health behavior (intervention) was MTM utilization. Outcomes were change (from baseline to 12-month follow-up) in: 1) Number of MHRPs; 2) Medication adherence measured by the medication possession ratio (MPR); and 3) Total drug costs. Descriptive and inferential statistical analyses were conducted. RESULTS: The intervention (n=60) and control (n=60) groups were not statistically different regarding age (71.2±7.5 vs.73.9±8.0), medications (13.0±3.2 vs.13.2±3.4), chronic diseases (6.5±2.3 vs.7.0±2.1) or MRC [(21.5 (range 8–43) vs.22.8 (range 9–42.5)], respectively. The majority (51%) were male in the intervention group but only 28% were male in the control group (p=0.009). At baseline, 4.8± 2.7 (intervention group) and 9.1± 2.9 (control group) MHRPs were identified and 2.2±2.0 and 7.3±3.0 MHRPs remained at the 12-month follow-up, respectively. Multivariate regression revealed that MHRPs decreased significantly (p=0.0120) among the intervention group when compared to the control group. There were no significant predictors of change in MPR. Total drug costs (change from baseline to follow-up) decreased by $588±$2,086 in the intervention group and increased by $207±$1,752 in the control group. A t-test indicated the cost difference between the 2 groups was significant (p=0.03), but the multivariate regression did not indicate significant predictors. CONCLUSIONS: A telephone MTM program positively impacted MHRPs. Unadjusted cost comparisons also showed cost savings among the intervention group. Future research should focus on understanding predictors that impact adherence and cost-related MTM outcomes.