Authored by Kelly Noonan, Rider University, National Bureau of Economic Research; Nancy E. Reichman, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey; and Hope Corman, Rider University, National Bureau of Economic Research. In this report, the authors estimate the effect of poor child health on the labor supply of new fathers post- welfare reform, using a national sample of mostly unwed parents and their children--a group at high risk of living in poverty. The researchers address the potential endogeneity of child health and find that having a young child in poor health reduces the father's probability of being employed by eight percentage points and that it reduces his work effort by over five hours per week. These results add to a growing body of literature suggesting that young children with serious health problems are likely to receive lower levels of health investment than their healthier peers.