We examine the effects of the 2010 Patient Protection and Affordable Care Act’s (ACA) prohibition of preexisting conditions exclusions for children on job mobility among parents. We use a difference-in-difference approach, comparing pre-post policy changes in job mobility among privately-insured parents of children with chronic health conditions vs. privately-insured parents of healthy children. Data come from the 2004 and 2008 Survey of Income and Program Participation (SIPP). Among married fathers, the policy change is associated with about a 0.7 percentage point, or 35 percent increase, in the likelihood of leaving an employer voluntarily. We find no evidence that the policy change affected job mobility among married and unmarried mothers.