Research Findings: This study used data from a national sample to examine differences in school outcomes at the end of kindergarten between Head Start children who attended full-day and half-day programs. Propensity scores were used to match children who experienced different intensities of the program on a series of demographic characteristics in order to achieve a more unbiased estimation of the intensity effect. Analyses were performed on 2 different age cohorts: 3-year-olds who enrolled in the program for 2 years and 4-year-olds who enrolled in the program for 1 year. The results showed that in comparison to a demographically comparable group of children who attended the Head Start half-day program, children who experienced the more intensive full-day program showed no significant differences on any of the 5 academic and social outcome measures examined. Practice or Policy: Policy and practice implications, as well as future research ideas, are discussed within this context.