The Omnibus Budget Reconciliation Act of 1990 enacted a refundable tax credit for low-income working families who purchased health insurance coverage for their children. This health insurance tax credit (HITC) existed during tax years 1991, 1992, and 1993, and was then rescinded. A difference-in-differences estimator applied to Current Population Survey data suggests that adoption of the HITC, along with accompanying increases in the Earned Income Tax Credit (EITC), was associated with a relative increase of about 4.7 percentage points in the private health insurance coverage of working single mothers with high school or less education. Also, a difference-in-difference-in-differences estimator, which attempts to net out the possible influence of the EITC increases but which requires strong assumptions, suggests that the HITC was responsible for about three-quarters (3.6 percentage points) of the total increase. The latter estimate implies a price elasticity of health insurance take-up of −0.42. Copyright © 2013 John Wiley & Sons, Ltd.