BACKGROUNDTreatment adherence is a primary key in controlling diabetes disease. The study aims to determine the prevalence of treatment adherence in type 2 diabetes mellitus (T2DM) patients, investigate the potential influence of adherence on elevated blood glucose levels, and identify the key factors which play a role in non-adherence to the prescribed drugs.METHODA cross-sectional study method was utilized to collect data from all T2DM patients at the Diabetic and Endocrine Centre and Shar Hospital in Sulaymaniyah city in the Kurdistan region of Iraq from February 2022 to April 2022. The data collection was performed through a structured questionnaire. The prevalence of drug adherence was assessed using the Morisky Medication-Taking Adherence Scale (4-item), and the glycated hemoglobin test (A1C) was used to determine the blood glucose level.RESULTA total of 300 participants were studied, and more than half of them (192; 64%) revealed that they did not adhere to their anti-diabetic medications. Non-adherence was significantly associated with higher A1C. Several barriers to non-adherence were identified as multiple medications, feeling the dose given is high, lack of finance, and side effects by 209 (70%), 116 (39%), 113 (38%), and 103 (34%), respectively.CONCLUSIONThe current study's result revealed that most T2DM patients have no adherence to their medication. This non-adherence is significantly linked to higher A1C levels, emphasizing the critical role of medication compliance in managing diabetes effectively. The study also sheds light on the multiple barriers such as taking multiple prescriptions, the perception that the dose is excessive, lack of finances, and experiencing side effects, which contribute to non-adherence among diabetes patients. These findings underscore the need for healthcare providers to address these barriers and develop tailored strategies to enhance medication adherence among individuals with diabetes.