Despite its potentially fatal side effect—agranulocytosis—clozapine has become an important drug in antipsychotic treatment. With this in mind, this report presents the case of a 23-year-old schizophrenic who had suffered from agranulocytosis after simultaneous short-term treatment with butyrophenone and phenothiazine neuroleptics 3 years ago. After nonresponse to two other classic neuroleptics, the administration of high-dose clozapine led to a full recovery without the recurrence of hematologic disorders during 24 months of follow-up examinations. Although patients with a known history of agranulocytosis are usually excluded from treatment with clozapine, we propose that, in very severe or otherwise therapy-resistant cases, clozapine be administered and then white blood cell counts monitored very stringently. Although a single case can prove little, our case provides further evidence for the presumption that noncross-reactivity exists between clozapine and other neuroleptic drugs in the induction of agranulocytosis.