Background: Out-of-pocket (OOP) payments for health care are highly pervasive in several low-and-middle income countries. The Cambodian health system has envisaged massive repositioning of various health care financing to ensure equitable access to health care. This analysis examines catastrophic, economic, as well as fairness, impacts of OOP health care payments on households in Cambodia over time. Methods: Data from two waves of a nationally representative household survey conducted in Cambodia (CDHS Surveys 2005 and 2010) were utilized. Healthcare utilizations based on economic status were compared during 2005 and 2010. Variables of interests were i) where care was sought and the instances of treatments, i.e. was treatment sought the first, second or third time; (ii) the mode of payment for treatment of the respondent or for any household member due to sickness or injury in the last 30 days prior to the survey period. Lorenz curves were applied to assess the degree of distribution of inequality in OOP expenditures between different income brackets. Results: The findings revealed that there was inequality and unfairness in health care payments, and catastrophic spending is more common among the poor in Cambodia. The majority of people from poorer households experienced economic hardship and have taken to catastrophic health care spending through sales of personal possessions. Conclusion: Based on the findings from this analysis, more attention is needed on effective financial protection for Cambodians to promote fairness. The government should increase spending on services being provided at public health care facilities to reduce ever increasing reliance on private sector providers. These approaches would go a long way to reduce the economic burden of care utilization among the poorest.