BRCA1 is known as a familial early onset breast cancer gene located in the long arm of chromosome 17. Alterations in this gene have been reported in different populations, some of which are population-specific mutations showing a founder effect. In this study, which is the first report on the genetic testing of Iranian women, exon-2 of the BRCA1 gene was sequenced in 80 Iranian breast cancer patients and none of the patients showed the 185del AG mutation or any changes in the sequences of this exon. Among this population, 22 patients having one or more of any kind of tumor in their first-degree relatives were selected and their entire BRCA1 gene coding region was sequenced by direct PCR-sequencing. A novel point mutation in exon-16, with unknown significance, was observed among the breast cancer patients and control subjects. This A/G mutation caused the substitution of Glutamine 1612 with Glycine, with an allele frequency of 38.6 and 52.8% in patients and controls, respectively. In addition, a point mutation in exon-15 and eight other polymorphic alterations were detected which have been reported previously. Three of these polymorphic sites were placed in the intronic part of the gene. To understand the significance of the contribution of the BRCA1 gene in the breast cancer among Iranian, further investigations are needed.