Velocardiofacial syndrome (VCFS) is associated with an increased frequency of schizophrenia and other types of psychiatric morbidity. In this study, we tried to identify a subgroup of schizophrenic patients with deletions in the VCFS region of the long arm of chromosome 22. For that purpose, we screened the records of two major general hospitals for patients with abnormalities characteristic of VCFS, such as cardiac anomalies and cleft palate, and crosschecked the data with the register of psychiatric hospitalizations in four psychiatric hospitals. Of the 24 patients that qualified, only seven patients could be studied. An additional eight schizophrenic inpatients were ascertained clinically, based on a working VCFS Clinical Scale. FISH studies and molecular analyses, using polymorphic markers from the VCFS region, documented hemizygosity of 22q11 in three out of 15 patients (20.0%). Increased awareness of psychiatrists to signs of VCFS among patients with psychiatric illnesses is encouraged, in order to direct molecular studies effectively. In order to cut down the cost of testing, we suggest screening suspected patients with a single marker, such as D22S941, and to study further only those who have a single electrophoretic band. Am.