Women identified or suspected as carriers of mutations in BRCA1 or BRCA2 susceptibility genes have a high risk to develop an early breast cancer and thus, require appropriate management. Some consensus guidelines were provided for women at hereditary risk and two possible strategies of prevention are suggested: breast cancer screening and prophylactic surgery. We present the French recommendations for breast cancer surveillance and discuss the justification, indications and modalities of mammographic screening. Screening by annual mammography is recommended from age 30 years in experienced centers, in association with semi-annual clinical breast examination from age 20 years. These recommendations apply to women who were identified as carriers of a cancer-predisposing mutation of BRCA1 or BRCA2 genes. In families for whom any mutation of the two genes could be identified, the same modalities apply also to women with a higher probability than 25% of being a carrier. We present here an illustration of the calculation of such probabilities from two example-pedigrees.