A small village has been identified in Southern Israel founded in 1949 by a clan of about 50 related individuals that arrived together from Central North Africa. Family legend claims that the clan lived together as an isolate in Central North Africa with exclusive endogamy for at least four generations. Overall prevalence of schizophrenia in the adult population is 2.5% (18/700) and for bipolar plus schizoaffective illness is 1.9% (13/700). Blood samples and interviews (SCID) are available from 28 patients with schizophrenia/schizoaffective disorder (20) or bipolar disorder (8) and 184 relatives. Microsatellite markers in candidate regions on chromosome 1,4,5,6,8,10,13,and 18 have been genotyped. A LOD score of 1.3 around marker IL9 on chromosome 5q31 was obtained for phenotype schizophrenia/schizoaffective disorder by multipoint analysis, and a NPL of 1.9 (P = 0.016) on chromosome 10p12.1. Both positions are within chromosomal regions where previously linkage with schizophrenia has been reported. No evidence for linkage was observed when bipolar was included in the phenotype definition.