Introduction: Diabetes mellitus (DM) is a chronic, non-communicable disease that has an increasing incidence rate overtime as well as increasing disease-related deaths. Furthermore, around half of diabetic patients are unaware actually about their disease, and more are not taking their medications. This study aimed to determine the extent of medication adherence and factors contributing to non-adherence among diabetic patients in Majmaah governance, Saudi Arabia. This is an observational cross-sectional study design conducted among patients with type 2 diabetes. A self- administered questionnaire was distributed among diabetic patients .The questionnaire consisted of sociodemographic data, HbA1c level, duration of DM, family history of DM, DM medications and 12-Item Medication Adherence Scale. 180 patients with diabetes type 2 were involved (71.7% females vs. 28.3% males). The prevalence of patients with uncontrolled HbA1c levels was 25%. Family history of DM constitutes 74.4%. The most preferred route for drug administration was oral (50.6%). High nonadherent to medication was found among 57.8%. The independent significant factor associated with high non-adherence to DM medication was uncontrolled HbA1c while being a female was the independent significant factor for low non-adherent to DM medication. The non-adherent of the diabetic patients regarding anti-diabetes medications was widely prevalent. Female patients tend to be more adherent to DM medication than their male counterparts. This study established the fact that uncontrolled glycated hemoglobin was a detrimental factor in adherence to anti-DM medications. More studies are required to raise the awareness of the diabetic population regarding the importance of medication adherence.