The study examined the validity of the Child Observation Record (COR). Participants were 242 children, a stratified, random sample of a large, urban Head Start program. Teachers trained to collect COR data provided assessments on the Cognitive, Social Engagement, and Coordinated Movement dimensions of the COR. Outcome data included cognitive and social-emotional outcomes in Head Start and indicators of early literacy in kindergarten. Biunivariate and bi-multivariate analyses were conducted. Convergent and divergent validity was established for the COR dimensions. The Cognitive dimension showed the strongest relationships with early reading and mathematics skills, whereas Social Engagement was most highly correlated with persistence, pro-social interactions, and motivation to learn. Coordinated Movement was positively correlated with play interaction and inversely correlated with withdrawn, low-energy behaviors. The Head Start COR Cognitive dimension was the best predictor of letter-naming proficiency in kindergarten. (Contains 6 tables.)