PURPOSE: Women with BRCA1/2 mutations are faced with complex decisions about breast and ovarian cancer risk management. This study was conducted to determine the effect of a tailored decision support system (DSS) that provides individualized survival and cancer incidence curves specific to expected outcomes of alternative management strategies. PATIENTS AND METHODS: This was a double-blind, randomized controlled trial of 32 women with BRCA1/2 mutations. Primary outcome measures were decision satisfaction, cancer anxiety, perceptions of cancer risk given alternative management strategies, and management decisions. RESULTS: Twenty-seven women completed a 6-week follow-up. Women in the intervention arm (n = 13) reported significantly higher decision satisfaction at follow-up than women in the control arm (n = 14; adjusted mean difference, 9.7; P < .0005). The effect of the DSS was greater among women with low cancer anxiety at baseline than women with high cancer anxiety at baseline (P = .01 for interaction). However, the DSS did not significantly alter cancer anxiety at follow-up, perceptions of cancer risk given alternative management strategies, or management decisions. CONCLUSION: The presentation of individualized survival and incidence curves for alternative management options improves satisfaction about cancer risk management decisions among women with BRCA1/2 mutations without increasing anxiety or changing management decisions. The benefit of the DSS is greatest among women with relatively low cancer-related anxiety at baseline.