Aim: To evaluate and categorize the medication errors occurred in Cardiology department of tertiary care hospital, Erode, Tamil Nadu to improve the treatment outcomes. Settings and Design: The prospective observational study was carried out in the cardiology department of tertiary care hospital. Subjects and Methods: The study included the patients with cardiovascular disease admitted in the hospital. A separate medication error reporting form was designed and data were collected and analyzed. Results: A total of 417 cases of patients with cardiovascular diseases were collected. Out of 417 cardiac cases, medication errors were found in 301 cases, which counted to a total of 516 medication errors. Incomplete prescriptions (48.83%) were the most common errors occurred in cardiac patients followed by inappropriate use of decimal (11.04%) contraindication (8.33%), omission errors (7.55%) and monitoring errors (6.20%). Physician related factors (61.43%) were responsible for most of the errors. Majority of medication errors were coming under Category A (51.88%) and Category B (35.45%), this may be due to an environment which is susceptible to medication errors. Conclusion: The study concluded that more than half of the patients in the cardiology department would experience medication errors. Since there is always a possibility for the occurrence of errors due to mistakes that can be easily rectified, so making necessary interventions will reduce the incidence of medication errors and thus can improve the quality of care to the patients.