Introduction: In Malaysia, Diabetes Medication Therapy Adherence Clinic (DMTAC) in hospital settings significantly improved patients' glycaemic control and cardiovascular risk. Until now no randomised controlled trial of DMTAC has been done in a primary care setting where the access to subspecialist services (endocrinologists, expensive medication, etc.) is limited. The objective of this research is to compare the glycaemic control among diabetes mellitus (DM) patients between those received additional DMTAC service and those received normal clinic service in primary care settings. Materials and Method: This was a parallel, randomised controlled study. The selected participants were patients aged 18 to 70 years with type 2 DM on diabetic medication who were being treated in Kota Samarahan Health Clinic with HbA1c above 8% and who never attended any education of DM prior to the study. The control group received normal clinic visits with consultations by a medical officer. The intervention group received four or more DMTAC visits in addition to normal clinic visits. The primary outcomes were HbA1c while the secondary outcomes were the occurrence of severe hypoglycaemia, weight gain and medication compliance of patients. The subjects were randomised by numbered envelope opened chronologically by the investigator during the initial assessment. All health care professionals (nurse, lab staff and medical officer) except DMTAC pharmacist managing the subjects were blinded as there were no markings on the patients notes indicating that they were in this study. The demographic data was collected during screening while health data including glycated haemoglobin (HbA1c) levels were collected at baseline, sixth month and one year. Results: In all, 100 patients were randomised into control and intervention groups (n=50 per arm). The change of HbA1c in the intervention group (mean=-1.58) was significantly more than the control group (mean=-0.48) at 12 months with a mean difference of -1.10% (p=0.005, Cohen's d=0.627). Both study groups had similar significant changes of subjects from non-compliance to compliance (control group, n=11 vs. intervention group, n=10). The changes of BMI after 12 months between control group (0.24 kg/m2 ) and intervention group (0.24 kg/m2 ) was not significant (p=0.910). There were no episodes of severe hypoglycaemia detected in both groups. Conclusion: The addition of DMTAC service in primary care can improve glycaemic control among patients. The study was registered in the National Medical Research Register (Malaysia): NMRR-13-1449-18955 FUNDING: This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. All blood test was done in our setting.