Many children are reported by parents to exhibit problems of conduct at home, and similarly many children are reported by teachers to exhibit conduct problems at school. Surprisingly, very little research has examined the extent to which children exhibit behavioural problems in the clinical range at both home and school. The current study examined the co-occurrence of problems at home and school in a sample of 189 children in schools in Victoria. The total sample consisted of (a) 124 children whose parents responded to invitations to participate distributed through schools, and (b) 65 children who had been referred to various agencies because of conduct problems. The occurrence of problems at home was assessed using the Child Behaviour Checklist (Achenbach & Edelbrock, 1983), and problems at school were assessed using the Teacher Report Form (Achenbach & Edelbrock, 1986). For the school sample, 7 children (5.6%) exhibited conduct problems in both settings (scores in the borderline/ clinical range), with 27 children (21.7%) exhibiting them in one setting only. For the clinic sample, 39 children (60.0%) exhibited problems in both settings, with 21 children (32.3%) exhibiting them in one setting only. The results of this study indicate the need for interventions that can be used consistently across home and school settings, as well as independently in single settings when warranted.