In the provision of health services, health institutions should be perceived as an enterprise to use limited resources most effectively and efficiently, evaluate them optimally and ensure production efficiency. Therefore, cost information enables the most efficient utilization of resources in hospital enterprises and allows managers to use decision-making mechanisms most accurately. This study was conducted to determine and compare the costs of prolonged hospitalizations in the cardiovascular surgery intensive care unit of a university hospital. Our study was descriptive and retrospective. The hospitalizations in the cardiovascular surgery intensive care unit of the hospital were analyzed according to the prolonged hospitalization criteria determined by the social security institution. 29 extended hospitalization patient bills were determined in three years. The mean age of the prolonged hospitalization of patients was 67 years, the duration of hospitalization was 680 days, and the mean hospitalization day was 18.64. The items with the highest expenditure in prolonged hospitalization of patients were determined as drug costs, general applications and intervention costs, medical consumables costs, and laboratory costs. The increase in costs during the hospitalization and treatment process is mainly due to medication, general practices, interventions, and medical consumables. Related decision-makers should make root-cause analyses, and plans should be made to reduce costs.