OBJECTIVES: This study aims to explore suitable method for measuring willingness-to-pay per quality-adjusted life year (WTP per QALY) in Thai population. METHODS: A cross-sectional survey was conducted among 250 Thai populations. Three methods of measuring utility, namely Standard Gamble (SG), Time-Traded Off (TTO), and Visual Analog Scale (VAS) were examined, while, two methods of measuring willingness-to-pay (WTP), namely open-ended and bidding method were employed. Each participant was asked for the value of utility and WTP amount for treatment and prevention of one of the following three health states: 1) blindness; 2) paralysis; or 3) allergy. The WTP per QALYs, was calculated from 6 groups of participants according to the selected health state and duration of being in the selected health state (i.e. five year VS rest of life), by dividing the WTP amount by the QALYs gained from treatment or prevention. Discount rate of 3% was used in this study. RESULTS: WTP per QALYs obtained from different utility measure methods, WTP methods, health scenarios, and duration of being in the selected health scenario varied significantly. From this study, the WTP per QALY in treatment scenario and prevention scenario obtained from 6 groups of participants ranged between approximately 3,500 to 120,000 Baht, and between 1,200 to 40,000 Baht, respectively. CONCLUSIONS:By using the value of WTP per QALY as the ceiling threshold for determining the cost-effectiveness of health interventions, several points identified from the findings of this study should be concerned. First, TTO and VAS technique should be employed for measure utility while bidding technique should be used instead of open-ended technique. Secondly, 5-year being in the health state scenario yields more reliable value of WTP per QALY, as compared to rest of life being in the health state scenario. Finally, the representativeness of the sample should be of concerns.