This study measures the elasticity of taxable earnings to the marginal tax price, identified by a marriage penalty relief provision contained in the Economic Growth and Tax Relief Reconciliation Act of 2001. The change in joint taxable earnings in response to the provision implies a joint elasticity ranging from 0.217 to 0.304. The joint response is driven by the taxable wage earnings of males, and does not reflect a shift in income from tax-deferred to taxable compensation, but an increase in total wage earnings.