OBJECTIVES: Mutations in BRCA1 and BRCA2 genes are associated with an increased risk of breast and ovarian cancer. If a BRCA mutation is detected in women with ovarian cancer their unaffected relatives may be offered genetic testing and prophylactic surgery. The long-term cost-effectiveness of providing BRCA testing to women with ovarian cancer and to their unaffected female first-degree relatives in the UK has previously been evaluated using a lifetime Markov model, but the approach had a number of limitations. The current study will employ a hybrid discrete event simulation (DES) structure that addresses some of the Markovian limitations associated with the previous model and will differentiate between BRCA1 and BRCA2 mutations and will consider results for a number of possible UK family pedigrees. METHODS: A hybrid DES will be constructed with a lifetime horizon, to evaluate the cost-effectiveness of BRCA testing in women with ovarian cancer and their female first- and second-degree relatives versus no testing. The model will consider the incidence of ovarian and breast cancer, differentiating between those with BRCA1 and BRCA2 mutations, as well as the associated mortality rates. Individuals identified as BRCA1 or BRCA2 positive will be eligible to undergo bilateral mastectomy and bilateral salpingo-oophorectomy, which significantly reduce the risk of both ovarian and breast cancer. RESULTS: Results will be presented as an incremental cost-effectiveness ratio expressed as a cost per quality adjusted life year (QALY). These will be compared to the UK cost-effectiveness threshold of £20,000 per QALY gained. A number of sensitivity and subgroup analyses will be presented alongside the base case. CONCLUSIONS: We aim to demonstrate that screening patients with ovarian cancer and their first- and second-degree relatives for the BRCA1 and BRCA2 mutation is cost-effective and reduces the incidence of breast and ovarian cancer in the population.