The most common mutations in the BRCA1 gene in the families with an increased risk of breast and/or ovarian cancer in Slovenia are c.181T > G, c.1687C > T, c.5266dupC, c.844_850dupTCATTAC and c.181T > A. The most frequent mutations in BRCA2 are c.7806-2A > G, c.5291C > G and c.3975_3978dupTGCT. This evidence concerns the gene BRCA1 and ovarian cancer.