This study evaluates the effectiveness of state child safety seat laws in the United States. Data for all 50 states for the period 1975 to 1994 are used. Pooled time series analysis is employed to estimate a model of the rate of fatalities suffered by children ages 0–5 years as occupants in automobile crashes. The occupant fatality rate for children 6–11 years of age is used as a comparison group to control for other trends not introduced in the estimated models. The results show that child safety seat policies have significantly reduced fatality rates among children 0–5 years of age. For each additional year of age covered by a state statute, this fatality rate drops 4.8%. A similar reduction in the fatality rate of the older age cohort (6–11 years old) was not observed.