To clarify why patients with schizophrenia show déjà vu experiences less frequently, we studied déjà vu experiences in 113 schizophrenic patients in relation to psychopathologies and antipsychotic medication. Déjà vu experiences were observed in 53.1% of the schizophrenic patients. Patients with increased negative symptoms (blunted affect, motor retardation, emotional withdrawal, conceptual disorganization, and mannerisms) had déjà vu experiences less frequently. The other psychopathologies were not significantly associated with presence of déjà vu experiences. The dosage of antipsychotic drugs was significantly correlated with the frequency of déjà vu experiences. This correlation was not affected by their psychopathologies at the time of examination. The decreased frequency of déjà vu experiences in patients with schizophrenia may be mainly due to the negative symptoms. The positive relation between frequency of déjà vu experiences and the dosage of neuroleptics remains uncertain.