In this study, long-term intellectual functioning and school-related behavioural outcomes were assessed in a patient sample that underwent invasive treatment for congenital heart disease (ConHD) between 1990 and 1995. The Wechsler Intelligence Scale for Children-Revised was used to measure intellectual functioning and the Teacher's Report Form to assess teacher-reported behavioural and emotional problems. Overall, patients had IQ scores that fell within the normal range. The total sample of ConHD children (N=117, 7-16 years old), however, obtained significantly lower mean scores on Verbal IQ and Verbal Comprehension than reference children. When compared with same-aged reference peers from the general population, 7-11-year-old ConHD children obtained significantly lower mean scores on Total IQ, Verbal IQ, Verbal Comprehension, and Perceptual Organization. In contrast, scores of 12-16-year-old ConHD children appeared to be significantly lower on Verbal Comprehension only and significantly higher on Performance IQ. No significant differences were found in intellectual functioning between ConHD boys and girls, nor between different diagnostic groups. The school-related behavioural and emotional adjustment of this sample of children with treated ConHD was favourable. Overall, this sample of recently treated ConHD children, and especially children aged 7-11 years, showed poorer intellectual functioning in several areas. These findings deserve further attention.