This paper examines the noncustodial parent earned income tax credit (NCP EITC), a new type of credit recently enacted in New York and Washington, D.C., and proposed by Senator Bayh and then-Senator Obama in 2007. The NCP EITC offers an earned income tax credit to low-income noncustodial parents who work and pay their full child support. This paper provides background information about the policy and presents national estimates of eligibility and benefits for an NCP EITC under three alternative policy scenarios. It also discusses several key design and implementation issues. © 2010 by the Association for Public Policy Analysis and Management.