The atypical antipsychotic clozapine was examined for its ability to interrupt cognitive functions in mice on passive avoidance paradigm and elevated plus maze. The posttraining intraperitoneal injection of clozapine (0.1-7.5 mg/kg) induced dysfunction in acquisition as well as retrieval, which was reversed by physostigmine (0.05 mg/kg). Clozapine showed dose-related effects on scopolamine-induced cognitive dysfunction, with higher doses having no significant effect and lower doses reversing the dysfunction. These results are explained on the basis of clozapine's effects on central cholinergic receptors.