To determine if parents whose children had undergone successful cardiac surgery perceived their children any differently from parents of children who had not undergone surgery, we used the Achenbach Child Behaviour Checklist (CBCL) to compare parent and teacher perceptions in these two groups. Subjects included 168 children who had undergone cardiac surgery 4 to 8 years previously and 51 controls. On the behaviour scale of the CBCL, the teacher's mean t scores showed no significant difference between the cardiac and control groups, in contrast to the parents' scores where parents perceived a higher degree of behavioural problems in children who had undergone cardiac surgery. On the social competence scale of the CBCL, the parents scored their children who had undergone cardiac surgery as less socially competent than did the parents of the controls. Teachers' scores showed no difference between groups.