Introduction: Measurement of financial support for health services is determined by household out of pocket expenditure for health which is associated with two approaches: catastrophic and impoverishing health expenditures.

Therefore, this study aimed to investigate the catastrophic and impoverishing health expenditure in Tehran urban population.

Method: This cross-sectional study was conducted in Tehran in 2013. The data were collected through interview and observation using a household expenditure questionnaire. In order to estimate the effects of factors affecting catastrophic health expenditure and impoverishing health expenditure, data analysis was done using Pearson test, one variable and multivariate logistic models, Excel and STATA Software.

Results: According to the finding 2.4% of households fell below the poverty line, 6.7% of families households had to pay out of pocket, and 3.8% were identified as facing catastrophic health expenditures as a result of out-of-pocket payment for health.

Conclusion: There are some key factors influencing health expenditure, such as head of household education level, the presence of people over 60 years in household, the use of inpatient services and the volume of use. Therefore, it is recommended that health policy makers and insurance organizations implement health insurance plans and reduce the health services tariff and out of pocket expenditure on health.

Keywords: Out of Pocket, Catastrophic Health Expenditures, Impoverishing Health Expenditures.