BACKGROUND: Illness perceptions (IP) involve coping strategies and behavioural responses that can influence glycaemic control. Despite the importance of good glycaemic control, the majority of patients in Asia are not achieving glycaemic targets. An evaluation of IP in association with glycaemic control, medication adherence and chronic kidney disease (CKD) in Type 2 diabetes mellitus patients (T2DM) was carried out in an outpatient setting in Malaysia METHOD: A cross-sectional study was conducted using the Revised Illness Perception Questionnaire in a purposive sample of 384 T2DM patients.RESULTS: There were 55.7% females, median age was 58.2 years and median duration of diabetes was 13 years. The majority (79.4%) of patients had poor diabetes control (HbA1c ≥ 7.0%) and 39.6% of patients had low medication adherence. Patients with good glycaemic control had a higher Timeline Acute/Chronic and Emotional Representations score, hence they held the correct belief that diabetes is chronic and experienced negative emotions. Highly adherent patients had a higher Illness Coherence (χ2 = 21.385, p