This study investigated the Infant Behavior Record (IBR) as an observer-rated measure of temperament. The aim was to determine whether the IBR and a parent-rated measure of temperament were comparably associated with children's performance on laboratory tasks and with a measure of the home environment. We found several significant associations between the IBR and laboratory performance and no significant correlations between parent ratings and laboratory performance. Conversely, there were several significant associations between parent-rated temperament and the home environment and no significant associations between the IBR and the home environment. These findings lend evidence to the utility of the IBR as an observer-rated measure of temperament that can be used by teachers, clinicians, and other professionals working with children.