To evaluate patients' adherence to evidence-based therapies at an average of 2 years after discharge for Acute Coronary Syndrome (ACS) and to identify factors associated with non-adherence. This study was conducted at Hospital Pulau Pinang, Malaysia. A random sample of ACS patients (n=190) who had discharged on a regimen of secondary preventive medications were included and followed up over a three follow-up appointments at 8, 16, and 23 months post discharge. At each appointment, patients were interviewed and given Morisky questioner to complete in order to compare their level of adherence to the prescribed regimens across the three consecutive time periods. Majority of patients reported either medium or low adherence across the three time periods with only small portion reported high adherence. Furthermore, there was a significant downward trend in the level of adherence to cardio protective medications during the study period (p<0.001). This study also identified 6 factors-age, gender, employment status, ACS subtype, number of co morbidities and number of prescription medications per day that may influence Patients' adherence to their medications. Our findings suggest that long-term adherence to secondary prevention therapies among patients with ACS in Malaysia is sub optimal and influenced by many demographic, social as well as clinical factors.