These findings draw attention to the feasibility of incorporating equity measurement into census data. Thailand has achieved both an impressive average decrease in U5MR and substantial reductions in U5MR inequality over a 10 year period. Contributing factors include overall economic growth and poverty reduction, improved insurance coverage, and a scaling-up and more equitable distribution of primary health-care infrastructure and intervention coverage. Understanding the factors that have led to Thailand's success could help inform countries struggling to meet the fourth MDG and reduce inequality.