106 familial and 592 sporadic ovarian cancer cases were analyzed to determine the frequency of the six most common mutations of the BRCA1 gene in the Greek population, namely c.5266dupC, p.Gly1738Arg, p.Arg1751X, deletion of exon 20 (c.5256_5277+3179del3200), deletion of exon 24 (c.5468-285_5592+4019del4429_insCACAG) and deletion of both exons 23 and 24 (g.169527_180579del11052). This evidence concerns the gene BRCA1 and ovarian cancer.