Clozapine is a dibenzodiazepine derivative with established antipsychotic efficacy in adult patients with schizophrenic psychoses. There are more than 15 studies that have also demonstrated the antipsychotic efficacy of clozapine in childhood and adolescent schizophrenia. The main advantages of clozapine treatment in this age group in comparison with typical antipsychotics are: (i) high antipsychotic efficacy during an acute schizophrenic episode; (ii) better improvement in chronic cases with a high load of negative symptoms; and (iii) markedly fewer extrapyramidal adverse effects and, therefore, fairly good tolerability. However, because of its possible adverse effects on the haemopoetic system (granulocytopenia, agranulocytosis), clozapine should not be used as first-line antipsychotic medication. Other adverse effects are related to the cardiovascular system (hypotonia, tachycardia or arrhythmia), the central nervous system (epileptic seizures, fever) and liver function (transient increases in levels of hepatic transaminases). Two other frequent adverse effects are hypersalivation and body-weight gain, which may present a particular problem in adolescents and young adults. Careful monitoring of haematological parameters and other adverse effects are preconditions for a successful treatment programme.