OBJECTIVES: To examine the effectiveness of an employer-sponsored, pharmacist-provided medication therapy management (MTM) program by evaluating changes in patient knowledge and clinical outcomes over one year in patients with diabetes. METHODS: A prospective pre-post longitudinal study. Three 10-question knowledge tests were developed collaboratively by an expert panel of clinical pharmacists and researchers, as part of the MTM program. Throughout the duration of the program, pharmacists administered the tests to City of Toledo employees and their dependents with diabetes, at baseline, six months and twelve months. The tests were designed to assess patients’ understanding of the causes, symptoms and clinical goals associated with diabetes, hypertension and hyperlipidemia. Based on the test results, pharmacists were able to tailor counseling sessions by educating patients based on the questions answered incorrectly. Clinical data were simultaneously recorded at three-month intervals over one year, and included the following variables: A1c, systolic blood pressure (SBP) and diastolic blood pressure (DBP). Data were analyzed with SPSS v16.0 using descriptive statistics, and Wilcoxin tests. RESULTS: One hundred and one patients enrolled in the MTM program. Diabetes knowledge improved for 29 patients (58.00%; p<0.001) after only 6 months. Hypertension test scores improved for 15 patients (65.22%; p<0.01) after 1 year. Of those patients, reductions in SBP and DBP towards goal were seen in 11 (73.33%, p=0.023) and 15 patients (100%, p=0.001), respectively.  Overall, 41 patients (56.16%; p=0.042) reduced their A1c towards goal within three months; 22 patients (59.46%; p=0.050) were able to decrease their SBP towards goal, whereas 24 patients (64.86%; p=0.018) reduced their DPB towards goal after 12 months in the program. CONCLUSIONS: This community pharmacy MTM program has effectively shown that consistent patient education delivered by a clinical pharmacist can have a positive impact on knowledge of disease for patients with diabetes while improving clinical outcomes concomitantly.