This study aims to examine the determinants of health expenditures in OECD countries and and assess the impact of health systems on these determinants. In this direction, it is constructed a panel cointegration regression model with the annual data of 27 OECD countries between 1995-2020 years. In addition, since this study aims to understand the effects of health systems on the determinants of health expenditures, health systems are modeled separately. For this reason, in the first model it was examined the data of 27 OECD countries. In the second model, it is modeled the data of 14 countries that have adopted the Beveridge health and in the third model, it modeled the data of 13 countries that have adopted the Bismarck health system. In order to obtain accurate results from the analyses, it was conducted the tests to the that required by panel cointegration analysis. In this direction, first of all, homogeneity and cross-section dependence tests were performed to the series. According to result of these tests, it was determined that the series are heterogeneous and they have cross-section dependence. Therefore, second generation panel unit root tests based on heterogeneity were applied to the series. The unit root tests revealed that the series were stationary at the same degree. So afte that models were constructed. Then homogeneity and cross-section dependence tests were conducted for the models and it was revealed that all three models were heterogeneous and have cross-section dependence. In the next stage, the models were tested for cointegration. Finally in the last stage, it was evaluated the results of the CUP-FM cointegration estimator. As a result of this estimation, it is revealed that health systems have an impact on the determinants of health expenditures.