Background: Various methods have been utilized to evaluate and test patient adherence to medications and there is no "gold standard" measure of adherence to medicines. Objectives: To investigate the extent of non-compliance to diabetes treatment and its contributing factors among diabetic patients attending the Diabetes Center at Arar city, Northern Saudi Arabia. Methods: A cross-sectional study was carried out among the target population. Patients already diagnosed to have type 2 DM for at least one-year duration and who were on antidiabetic medication for more than 6 months, aged at least 18 years, attending the diabetic center during the study period, and giving written informed consent to contribute in the study. The collection of data was via personal interviews with diabetic patients. The instrument of data assortment was a structured questionnaire that consists of three sections: section 1 for the Socio-demographic features of the patients as age, sex, marital state, and occupation; section 2 contained questions that assess the adherence patterns by eight-item Morisky Medication Adherence Scale (MMAS-8). Results: According to MMAS scores of DM treatment adherence, the majority (79.8%) of the respondents were poorly adherent, 14.6% were mediumly adherent, and only 5.6% were highly adherent. Significant factors affecting the poor adherence to DM medication were gender, glycosylated hemoglobin level, believing the medication is ineffective, suffering from side effects of the medication, and using alternative medicine (P<0.05). There was a statistically insignificant factor as, educational level, suffering DM complications, period of DM, route of drug administration, receiving DM health education in the last 6 months, understanding the drug regimens, and affordability of the prescribed drugs. Conclusion: In the current study in Arar, Saudi Arabia, the majority of the diabetic patients were poorly adherent to DM treatment.