Yemeni diabetic patients believe that khat chewing helps to lower their blood glucose. Different studies suggested that substance use especially khat chewing in diabetic patients is associated with poor adherence to treatment and outcomes, resulting in mortality and morbidity. Health professionals require greater awareness of khat use and related health problems. The aim of the study was to explore the effect of educational program about khat abusing on Self-Care Adherence for diabetic patients in Sana'a, Yemen Republic. Subjects and Methods: The total number of selected adults diabetic patients abusing khat both male and female attending to educational program in outpatient diabetic center of Al Thawra Modern General Hospital at Sana'a, Yemen Republic from September 2014 until the end of July 2015 were 116. Tools: Patient Assessment Questionnaire, Adherence to Self-care scale and Severity of Dependence Scale-Khat were utilized for data collection. Results: There was a strong improvement in Self-Care Adherence p < 0.001** and there was negative statistically significant correlation between self-care adherence level and Severity of Dependence Scale-khat score (Pearson coefficient r = -.251*, p < 0.012). Conclusion: there was improvement of Self-Care Adherence for less addicted and there was negative relation between the level of khat abusing dependence and self-care adherence.