Background: Insight has been reported as one of the most relevant factors associated with medication adherence. It is the key element in schizophrenia and Bipolar Affective Disorder outcomes through its direct effect on disability and adherence. Poor adherence to prescribed regimens can result in serious health consequences. Aim: The purpose of this study is to explore the relationship between insight and medication adherence in patients with schizophrenia and Bipolar Affective Disorder (BAD). Method: A crosssectional study was conducted for a duration of 6 months on 60 patients (30 patients of bipolar affective disorder and 30 patients of schizophrenia). Patients of schizophrenia and BAD from inpatient and outpatient department fulfilling the inclusion criteria were selected. Socio-demographic data is collected using specially designed proforma. Insight was assessed using Beck cognitive insight scale (BCIS) , treatment adherence by Drug Attitude Inventory scale (DAI). Result: In this study it was observed that, correlation between insight and drug adherence scores in patients of schizophrenia and bipolar affective disorder is positive and strong and statistically significant (P value- 0.001). This study shows that Insight is an important factor which decides the drug adherence. There may be many other factors which influence the drug adherence. However, insight has a direct association with drug adherence in patients of bipolar affective disorder and schizophrenia.