Seventy-nine children, independently diagnosed as having attention deficit disorder (ADD) with or without hyperactivity and ranging in age from 6 years, 0 months, to 12 years, 11 months, were administered the Wechsler Intelligence Scale for Children-Revised (WISC-R), the Wide Range Achievement Test (WRAT), and the Child Behavior Checklist (CBC). Multiple regression analyses indicated a significant multiple correlation between age and achievement variables (R=0.42, p=0.003) and age and behavioral (CBC) variables (R=0.55, p=0.01). Post hoc analyses indicated that much of this variance was accounted for by a significant negative association between age and Full Scale IQ-WRAT Arithmetic difference scores, and significant positive correlations between age and scores on the Social Withdrawal and Uncommunicative scales from the CBC. A nonparametric chi-square analysis indicated that older children with ADD are significantly more likely (p=0.037) than younger ADD children to have a discrepancy of 15 or more points between IQ and math achievement scores. Results suggest that older ADD children are more likely than younger ADD children to experience academic and socioemotional difficulties. J Dev Behav Pediatr 11:22-26, 1990.