An open trial of clozapine was carried out in five patients with childhood-onset schizophrenia (COS). The standard protocol for administering and monitoring of clozapine was followed. Psychopathology was measured using the Brief Psychiatric Rating Scale and global clinical improvement was rated by a parent and two clinicians in each case. The level of improvement in positive symptoms was greater than that in negative symptoms with no effect on ritualistic behaviour. Global clinical improvement was substantial. No serious side-effects (seizures, agranulocytosis) were observed. The need to assess the differential clinical effects and establish the role of clozapine as a possible first choice antipsychotic in COS is highlighted.