Background: Diabetes is a common costly condition associated with significant morbidity and mortality. The process of teaching individuals to manage their diabetes had been considered an important part of the clinical management. The goals of self-management education are to optimize metabolic control, prevent acute and chronic complications, and optimize quality of life; Aim: To evaluate the impact of a health education intervention guidelines for T2DM on Patients' knowledge, self-efficacy, and self-management practices. Methods: Design: quasi-experimental uncontrolled design on 50 patients evaluated at pre-intervention, post-intervention, and 6-month follow-up. Setting: The study was carried out in the outpatient clinics of Endocrinology and Metabolism at Zagazig University Hospital. Tools: three tools were used, 1st tool was an interview questionnaire to assess socio-demographic data and patients' knowledge, self-efficacy scale and patients' self-reported self-management behaviors concerning self-care practices. Results: There were statistically significant improvements in patients' knowledge (p < .001), self-efficacy (p < .001), and selfmanagement (p < .001), which continued through follow-up. Multivariate analysis showed that the knowledge and self-efficacy scores positively predicted the scores of self-management. Conclusions: The study demonstrates the effectiveness of health educational intervention guidelines in improving T2DM patients' self-management behaviors and self-care practices through provision of sound information and fostering their self-efficacy. The slight decline at the follow-up phase indicates the need for periodic booster doses of the intervention. Therefore, the study recommends generalization of such educational guidelines in all health care settings providing services to T2DM patients. Such guidelines should particularly address the patients with low educational attainments, long history of T2DM, and those residing in rural areas. More research is needed to investigate the long-term effect of such educational interventions.