The primary objective of this paper is to evaluate the impact of Taiwan's National Health Insurance program (NHI), established in 1995, on improving elderly access to care and health status. Further, we estimate the extent to which NHI reduces gaps in access and health across income groups. Using data from a longitudinal survey, we adopt a difference-in-difference methodology to estimate the causal effect of Taiwan's NHI. Our results show that Taiwan's NHI has significantly increased utilization of both outpatient and inpatient care among the elderly, and such effects were more salient for people in the low- or middle-income groups. Our findings also reveal that although Taiwan's NHI greatly increased the utilization of both outpatient and inpatient services, this increased utilization of health services did not reduce mortality or lead to better self-perceived general health status for Taiwanese elderly. Measures more sensitive than mortality and self-perceived general health may be necessary for discerning the health effects of NHI. Alternatively, the lack of NHI effects on health may reflect other quality and efficiency problems inherent in the system not yet addressed by NHI. Copyright © 2006 John Wiley & Sons, Ltd.