Background Non-adherence to prescribed treatment is a principle cause of treatment failure in patients with chronic diseases, such as type 2 diabetes mellitus (T2DM) and hypertension. Improved patient monitoring and education have been shown to improve adherence and clinical outcomes. Objective This study evaluates the impact of a pharmacotherapy optimization plan centered on patient education that was implemented at a hospital in Arauco, Chile. Methods A prospective study was conducted using 50 randomly selected patients diagnosed with both T2DM and hypertension. Each patient participated in three successive interview sessions over 6 months. At each session, the following variables were evaluated by a pharmacist: blood pressure, HbA1c, adherence to prescribed medication, and patient knowledge of disease. Results Significant decreases were observed for HbA1c (< 0.001), and SBP (< 0.001), with stronger and more significant decreases observed for females. Patient adherence to prescribed medication also improved, but not significantly. The number of patients with full knowledge of their diseases increased significantly (p < 0.001) from 10 to 66 %. Conclusion This study suggests that the incorporation of a pharmacotherapeutic optimization plan for patients with chronic diseases can have a positive impact on the control of chronic diseases, such as T2DM and hypertension.