Identification of founder mutations in various ethnic groups is important to improve genetic screening and cancer risk assessment because it makes a more specific approach for molecular testing that targets the founder allele possible, thus resulting in reduced cost of genetic testing and faster turnaround time. The high frequency of founder mutations in a given population provides a large patient cohort not only for robust information regarding penetrance but also accurate assessment of the effectiveness of preventive measures. Previously, our laboratory identified and reported a recurrent BRCA2 mutation in 4 unrelated probands in a cohort of 119 high-risk women [1]. All these probands were from Chinese ancestry and 81.5% were from Guangdong province of Southern China. The recurrent mutation c.3109C[T (p.Gln1037X) was located in exon 11 of BRCA2. By prediction, this mutation resulted in the creation of an early termination codon and a truncated BRCA2 protein product. The haplotype analysis confirmed the mutation to be a founder mutation of Southern Chinese. To date, BRCA mutations are scattered over all exons and thus genetic tests for these BRCA1/2 genes require a mutation screening method of the entire coding regions of the genes. In our laboratory, we currently offer BRCA1/2 mutation screening in Hong Kong to Chinese women with breast or ovarian cancer at age 45 years and below, or with a history of BRCA related cancer such as breast, ovarian, colon, prostate in the family using full gene sequencing. This BRCA1/2 mutation detection procedure is time-consuming and labor intensive. Recently, increasing numbers of reports use high-resolution melting (HRM) as a promising pre-screening method of gene scanning for rapid identification of BRCA1/2 variants [2–7]. HRM analysis is a new and useful method for fast genotyping and high-throughput mutation scanning of disease-associated genes in genome diagnostics [8–10]. To date, little is known about the penetrance of BRCA founder mutation in Chinese population. So far, apart from our recently identified BRCA2 founder mutation, only one other founder mutation in BRCA1 (1081delG) found in Southern Chinese population has been reported [11]. Thus, using our recently developed HRM assays, we determined the frequency of these two BRCA1/2 founder mutations in Southern Chinese population. Between March 2007 and September 2009, a total of 709 Chinese patients with breast and/or ovarian cancer were recruited from the Hong Kong Hereditary Breast Cancer Family Registry to perform BRCA1/2 genetic testing. Of these 709 patients, 705 are only breast cancer patients and 14 are both breast and ovarian cancer patients. The mean age at diagnosis of breast cancer was 44.6 years old (range 18–83) and that of ovarian cancer was A. Kwong E. K. O. Ng H. N. Wong V. W. Chan Division of Breast Surgery, Queen Mary and Tung Wah Hospital, The University of Hong Kong, Hong Kong, China