The impact of the universal coverage policy implementation in Thailand is demonstrated by the declining incidence of catastrophic health spending among Thai households-particularly among the poor. The households who remain at risk of catastrophe, as defined here, are better-off households, because of their preference for using private facilities. Others with increased likelihood of incurring catastrophic health expenditures are households with a greater proportion of elderly members, those having a member with a chronic illness or disability, and those having a member who experienced hospitalization. These determinants should prompt policy concerns to protect such households from financial catastrophe.