A predominant mutation within the BRCA1 predisposition gene, 185delAG, has been detected in about 1% of the Ashkenazi population, considered a high-risk group for breast and ovarian cancers. We examined 639 unrelated healthy Jews of Iraqi extraction, a presumed low-risk group, for the existence of this mutation. Three individuals were identified as 185delAG mutation carriers, and haplotype analysis of the Iraqi mutation carriers revealed that 2 of the Iraqis shared a common haplotype with 6 Ashkenazi mutation carriers, and 1 had a haplotype which differed by a single marker. This study suggests that the BRCA1 185delAG mutation also occurs in populations considered at low-risk for breast and ovarian cancers, and that it might have occurred prior to the dispersion of the Jewish people in the Diaspora, at least at the time of Christ.