Universal health coverage is one important policy recommendation by the World Health Organisation to governments in both developed and developing countries. Thailand was ambitious in setting the target to achieve this policy nationwide only a year after the majority vote victory in 2001 by putting up the 30 baht medical care policy. This research was to document the policy processes at the central and provincial levels during the first year of implementation, and to measure the impact of the policy at household level. The ultimate aim was to recommend on how to make the policy sustainable.This study employed three research methods in order to complement each other. The documentary reviews and qualitative methods were used to describe policy processes at the national and provincial levels, and outlined impacts of such implementations on health delivery systems. The third method employed a full-scale household health interview survey to measure policy impacts at household level. Four provinces were purposively selected from 21 piloted provinces since April 2001 and June 2001. In-depth interviews and focus group discussions were the main qualitative methods used with top executives, policy makers, and providers. Household surveys consisted of about 1,000 households in each province. It was revealed that the designs of the systems for pilot provinces in April and June 2001 were the day-to-day management style, whereas the decisions for full implementation since October 2001 have been a monthly management. Unstable policy decisions created turbulence till the end of 2001. The implementation of the policy at the ministry level faced with the discontinuity of capable responsible officers. Policy implementations at provincial level were critically at risk under the leaderships of provincial chief medical officers and provincial hospital directors. It seemed that provinces applying an inclusive outpatient-inpatient capitation budget faced additional risks on substandard quality of care by under referrals with the coincidence of weak leaderships. Household surveys revealed that the policy was highly supported by both the rich and the poor. Thai citizens have shifted from their libertarian views to slightly egalitarian views in reducing social policies, that discriminate the rich and the poor. When compared among three main health benefit schemes (civil servant medical benefit, social security and the 30 baht scheme), the 30 baht still faced with low compliance rates (use of their health benefits when they seek medical care) for both outpatient and inpatient services. However, the poor families complied at a higher rate than the rich, which means that the policy has at least achieved its main objective. Comparing equity of financing by out-of-pocket expenditure, the 30 baht scheme was inferior to the social security scheme in protecting the lower income families from financial burden of seeking health care. To attain sustainable coverage, recommendations on managing supply side are crucial.