Catastrophic spending on health care through out-of-pocket payment is a huge problem in most low- and middle-income countries all over the world. The collapse of health systems and poverty have resulted in the proliferation of the private health sector in Cambodia, but very few studies have examined the fairness in ease of utilization of these services based on mode of payment. This study examined the utilization of health services for sickness or injury and identified its relationship with people's ability to pay for treatment seeking at various instances. Based on cross-sectional data from the Cambodian 2007 Demographic and Health Survey, the economic index estimated through principal component analysis and Lorenz curve was used to quantify the degree of fairness and equality in utilization and payment burden among the respondents. A distinct level of fairness was found in health care utilization and out-of-pocket payments. Specifically, use of private health care facilities and over-the-counter remedies dominate, and out-of-pocket payments cut across all socioeconomic strata. As many countries in low- and middle-income regions, and most importantly those in transition such as Cambodia, are repositioning their health systems, efforts should be made towards maintaining equitable access through adoption of finance mechanisms that make utilization of health care services fair and equitable.