Possible effects of consistently applying published guidelines on healthy women with breast cancer in their family history were analysed. We investigated 1060 unrelated breast cancer patients and calculated the numbers of first-degree relatives that would be referred to a familial cancer clinic if the guidelines were consistently applied. A first-degree relative was considered a candidate for referral if she was female, without breast cancer at the moment of the interview, alive and over the age of 24. The criteria for referral were based on one Dutch and two British guidelines. According to the Dutch guideline, for one affected woman with breast cancer, 0.25 (95% CI 0.22-0.28) healthy first-degree female relatives should be offered a consultation at a familial cancer clinic (FCC). Application of the British guidelines would lead to a similar number of referrals. Of all healthy first-degree female relatives, who should be referred to an FCC, 34-37% had an index case among their family who was already known at a genetic department. If current guidelines are consistently applied, a sharp increase in referrals to FCCs may be expected. These guidelines, however, are arbitrary and only limited data are available on the efficacy of this surveillance for high-risk healthy women.