This study examines the relation between 3-year-old children's (N = 280) symptoms of inattention, hyperactivity, and aggression and their cognitive, motor, and preacademic skills. When the authors controlled for other types of attention and behavior problems, maternal ratings of hyperactivity and teacher ratings of inattention were uniquely and moderately associated with children's lower cognitive and preacademic skills. The few modest, simple associations between maternal ratings of aggression and children's skills were no longer significant when hyperactivity and inattention were controlled. This suggests that cognitive and preacademic problems among children with attention-deficit/hyperactivity disorder symptoms may begin to emerge as early as age 3. The results highlight the importance of examining the association between different types of behavior problems and young children's skills.