Vietnam's Health Care Fund for the Poor (HCFP) uses government revenues to finance health care for the poor, ethnic minorities living in selected mountainous provinces designated as difficult, and all households living in communes officially designated as highly disadvantaged. The program, which started in 2003, did not as of 2004 include all these groups, but those who were included (about 15 percent of the population) were disproportionately poor. Estimates of the program's impact-obtained using single differences and propensity score matching on a trimmed sample-suggest that HCFP has substantially increased service utilization, especially in-patient care, and has reduced the risk of catastrophic spending. It has not, however, reduced average out-of-pocket spending, and appears to have had negligible impacts on utilization among the poorest decile.