Foster care caseloads have nearly doubled over the last three decades. Parental methamphetamine (meth) use grew significantly during the same period. While child welfare workers and law enforcement claim that parental meth use contributes to foster care growth, the evidence for a causal effect has not been determined. This paper presents the first evidence of a causal effect of meth on foster care admissions using two exogenous supply-side interventions in meth markets from the late 1990s for identification. First, we find that restrictions on meth precursor distribution caused meth use (proxied by white meth self-referred treatment cases) to decline 4.1%. Second, using two-stage least squares, we estimate a positive elasticity of foster care cases with respect to meth use of 1.54. We also estimate elasticities of 1.03 and 1.49 for cases of child neglect and parental abuse, respectively. These results suggest that child welfare policies should be designed specifically for the children of meth-using parents. (JEL I12, J13, K42)