A questionnaire was sent to the teachers of 38 children being treated for leukaemia and also to the teachers of 19 siblings. The questionnaire was concerned with the child's attendance rate, the teacher's perceptions of the child and thirdly with his attainments and behaviour. Those with leukaemia had a poorer attendance record (41.5 per cent absences) than their siblings (15.6 per cent). Teachers reported special difficulties in teaching the leukaemic child, and had modified expectations regarding him. Children's attainments were comparable to other members of the class, although tending to be somewhat poorer. Teachers did not report any differences in attainments between siblings and other members of the class. The data indicate that closer liaison between school and hospital would be advantageous to teachers.