The aim of the study is to evaluate the efficacy of sertraline for controlling hot flashes in women with or at high risk of breast cancer. This was a randomized, double-blind, placebo-controlled study. All participants were asked to complete hot flash diaries. Participants reporting weekly hot flash scores >15 during baseline week underwent a 1-week single-blind placebo run-in. Those reporting hot flash score reductions >50% following placebo run-in were excluded. The remaining women received an assigned treatment for 4 weeks. Both groups' demographic and clinical characteristics were similar with a greater decline, but not statistically significant, in hot flash frequencies and scores in the sertraline-treated group compared with the placebo (P = 0.13 and P = 0.15, respectively). Emotional well-being improved significantly in the sertraline group (P = 0.041). The study failed to demonstrate effectiveness of sertraline in attenuating hot flashes in women with or at high risk of developing breast cancer who were not recommended to take hormone replacement therapy.