Objective: Drug-drug interaction (DDI) is of major concern in patients with complex therapeutic regimens. The involvement of cardiovascular medicines in drug interaction is even higher. However, reports of DDI between these groups of drugs are few. The present study is aimed to identify potential drug-drug interactions in cardiac patients and document any observed interaction in SMS Medical College, Jaipur, Rajasthan. Methodology: The prospective observational study was conducted from January 2017 to July 2017 among hospitalized cardiac patients. The data collected in predesign data collection for 200 patients, Cardiac patients prescribed at least 2 drugs and having hospital stay of more than 24hours duration were enrolled into the study. The collected data included demographics, cardiac drugs usage pattern and safety analysis data. The data was compiled in excel. Result:  The incidence of potential DDIs was 98% with 200 prescriptions having at least one potential DDI and 130 patient prescriptions contains pDDI. The incidence rate was found to be 62.50%. Majority of interactions were of moderate severity, delayed onset, and pharmacodynamics in nature. Total 28 actual interactions were observed in the observed cases. Out 200 drug interactions, aspirin/clopidogrel and clopidogrel/atorvastatin were most common drug interaction pairs observed among prescribed medications. Of the 200 interventions proposed, the most frequent suggestion was on monitoring for adverse effect (42.01%) followed by dose adjustment (16.83%). 27.55% of interventions were accepted and therapy was changed. Most of the adverse drug interaction observed resulted in bleeding. Conclusion: Drug–drug interaction in patients was common in this resource limited set-up.  Proper therapeutic planning, routine monitoring of cardiac in-patients and usage of online DDI database will avoid potentially hazardous consequences in cardiac in-patients. It was found that the incidence rate of pDDI was high and associated with old age, poly pharmacy and increased lengths of hospital stay. This study highlights the need for screening prescriptions of cardiovascular patients for pDDIs and proactive monitoring of patients who have identified risk factors; this helps in detection and prevention of possible adverse drug interactions.