The decline in health insurance coverage among workers from 1979 to 1995 can be accounted for almost entirely by the fact that per capita health care spending rose much more rapidly than personal income during this time period. We simulate health insurance coverage levels for 1996-2005 under alternative assumptions concerning the rate of growth of spending. We conclude that reduction in spending growth creates measurable increases in health insurance coverage for low-income workers and that the rapid increase in health care spending over the past fifteen years has created a large pool of low-income workers for whom health insurance is unaffordable.