Background: Ventilator-associated pneumonia (VAP) is associated with significant morbidity, mortality and healthcare costs. Most of the cost data that are available relate to general intensive care patients in privately remunerated institutions. This study assessed the cost of managing VAP in a cardiac intensive care unit (CICU) in the National Health Service (NHS) in the United Kingdom. Methods: Propensity-matched study of prospectively collected data from the cardiac surgical database between April 2011 and December 2014 in all patients undergoing cardiac surgery (n=3416). Patients who were diagnosed as developing VAP, as per the surveillance definition for VAP (n=338), were propensity score matched with those who did not (n=338). Costs of treating post-op cardiac surgery patients in intensive care and cost difference if VAP occurred based on Healthcare Resource Group (HRG) categories was assessed. Secondary outcomes included differences in morbidity, mortality and CICU and in-hospital length of stay. Results: There were no significant differences in the pre-operative characteristics or procedures between the groups. VAP developed in 10% of post-cardiac surgery patients. Post-operatively, the VAP group required longer ventilation (p<0.01), more respiratory support, longer CICU (8 v/s 3, p<0.001), and in-hospital stay (16 v/s 9) days. The overall cost for post-operative recovery after cardiac surgery for VAP patients was £15,124 compared to £6,295 for non-VAP (p<0.01). The additional cost of treating patients with VAP was £8,829. Conclusion: VAP was associated with significant morbidity to the patients, generating significant costs. This cost was nearer to the lower end for the cost for general ICU patients in privately reimbursed systems.