ObjectiveThe primary objective was to evaluate the impact of a pharmacist-delivered motivational interviewing (MI) intervention for diabetes medication adherence; the secondary objectives were to assess the changes in clinical outcomes and health-related quality of life (HRQoL). MethodsA quasi-experimental intervention study was conducted with baseline, postintervention, and follow-up data collections. The study duration was 6 months. Pharmacists trained in MI delivered 3 face-to-face encounters using MI-based semistructured conversation tools to address barriers or challenges to medication adherence. A diabetes worksite wellness program (WWP) at a 350-bed regional hospital in the southeastern United States was the setting, and the study participants were WWP employees or dependents (with type 1 diabetes or type 2 diabetes). The primary outcome was a change in self-reported diabetes medication adherence; the secondary outcomes included the changes in clinical indicators (glycated hemoglobin [HbA1c], blood pressure, and depressive symptoms), and HRQoL. The measures included the Medometer, Summary of Diabetes Self-Care Activities–Medication Subscale (SDSCA-MS), Audit of Diabetes-Dependent QoL (ADDQoL-19), and the Short Form–12 (SF-12) health survey. ResultsFifty-three WWP participants enrolled, and 36 completed the full intervention protocol. Medication adherence (through the Medometer) demonstrated statistically significant improvement after the intervention (P = 0.010); the SDSCA-MS score improved, but was not statistically significant. The change in diastolic blood pressure was statistically significant (P = 0.034), but the changes in HbA1c, systolic blood pressure, presence of depressive symptoms, and ADDQoL-19 were not statistically significant. The SF-12 physical component summary (PCS) and mental component summary (MCS) scores were statistically significant: PCS, P = 0.003, and MCS, P = 0.025. ConclusionThe findings from this pilot study support the effectiveness of a pharmacist-delivered, semistructured MI-based intervention for medication adherence in persons with diabetes in a hospital-based WWP. Pharmacists can support patients’ behavior change using MI communication skills to explore salient barriers to medication adherence and to facilitate goal setting to overcome these in encounters aimed at shared clinical and behavioral decision-making.