Background: Diet control, exercise and medication therapy are three main treatment regimens for diabetes mellitus. To ensure all three are properly fulfilled, patient compliance behavior is a key factor. Moreover, a good support system is one of the motivational factors for patient to continuously involve in treatment. In Taiwanese healthcare environment, most of the patient gathered in the pharmacy section after seeing a doctor. Introduction of pharmaceutical outpatient unit provides another way for disease treatment in our countries. Furthermore, the sufficient time will allow pharmacist to provide thorough pharmaceutical care and health education for chronic diseases. Purpose: This aim of this study is the effect of pharmacist on disease knowledge and to evaluate the level of disease improvement after pharmacist involvement. Method: This study was prospective and quasi-experimental design. 112 patients with type 2 diabetes were referred by physicians and assigned to groups A and B. Each group is consisted of 56 persons and each group received two stages of intervention. Group A was initially evaluated using the health literacy tool and stage 1 intervention was provided. This stage of education includes contains a correct understanding of disease and medication. 3 month later, patients were firstly evaluate and followed by stage 2 intervention. This stage of education includes emergency treatment concepts, blood glucose monitoring and self-care ability. 6 month later, final evaluation was given. For group B, patients were initially evaluated and no intervention given. 3 months later, patients were firstly evaluated and followed by stage 1 intervention. 6 month later, patients were final evaluation. Both groups were evaluated for their health literacy, disease knowledge, compliance, and health outcome. Result: The overall literacy scale improve from 70.3% to 86.7 (p ＜ 0.001). The mean of HbA1c were decrease by 0.5%. Conclusion: Disease knowledge and health literacy were significantly improved after pharmacist involvement.