OBJECTIVES: To evaluate the association of knowledge and medication adherence with glycemic control in patients with diabetes mellitus type 2. METHODS: The research was shaped as a cross-sectional, investigational study. Convenient sampling was done to identify a cohort of 540 diabetic patients attending diabetes clinic of Hospital Pulau Pinang, Penang, Malaysia. A previously validated knowledge test and medication adherence scale was used for data collection. Patients’ medical records were reviewed for haemoglobin A1C (HbA1C) levels and other disease-related information. RESULTS: Five hundred five patients were included in the final analysis, with a mean age of 58.15 years (SD=9.16) with 50.7% males having mean HbA1C of 7.94 (SD=1.61). Knowledge scores ranged from 0 to 14, with mean scores of 7.44 (SD=3.08). Medication adherence scores ranged from 0 to 8 with mean scores of 6.11 (SD=1.66). HbA1C was found to be significantly lower in patients with higher level knowledge and higher level of medication adherence (p<0.05). Significant correlations were found between the three variables HbA1C, Knowledge and adherence (p<0.05). Combined therapy, higher diabetes knowledge and higher medication adherence were statistically predictors of good glycemic control.  CONCLUSIONS: There is a high prevalence of poor glycemic control among patients in this study. This study revealed that knowledge and adherence are among the modifiable factors that are associated with better glycemic control.