Background: The prevalence of Diabetes Mellitus is growing at a dreadful rate across the globe. India is considered to have the highest population of diabetics in the world and this is a growing concern. Aim: To assess the adherence in diabetic patients towards treatment. Methodology: A Cross sectional study was conducted in tertiary care hospital, Tamil Nadu- during May 2017. Convenient method of sampling was adopted. All type 2 diabetic patients having age above 35year was recruited. Data was collected through face to face interview method by using structured questionnaire. A total of 200 diabetic patients from Tamil Nadu were included in this questionnaire-based study. Participants who fulfilled the eligibility criteria were approached in person and the necessary study specific data was collected. We used questionnaire namely Morisky Medication Adherence Scale to assess the subjects. The scores were calculated and examined. Results: About 71.5% of the total population had poor medication adherence scores 24% with medium medication adherence scores and 4.5% of them had high medication adherence. We were able to find four factors that influenced a patient’s level of adherence which were Forgetfulness (70%), Dietary restriction was difficult to maintain (72.5%). Not aware of the consequences of missing the dose (67.5%), Fear to becoming dependent on treatment (42.5%), Fear of side effect (42%). Conclusion: The fact that knowledge and self-awareness about one’s medical condition is vital to medication adherence. Healthcare professionals as well as patient need to be made aware of the relationship between knowledge and medication adherence. Continuous patient education is needed to improve patient adherence and attitude towards treatment.