The objective of this review was to assess the effectiveness of acupuncture as a treatment option for hot flashes in patients with breast cancer. We searched the literature using 14 databases from their inceptions to August 2008, without language restrictions. We included randomised clinical trials (RCTs) comparing real with sham acupuncture or another active treatment or no treatment. Their methodological quality was assessed using the modified Jadad score. Three RCTs compared the effects of manual acupuncture with sham acupuncture. One RCT showed favourable effects of acupuncture in reducing hot flash frequency, while other two RCTs failed to do so. The meta-analysis show significant effects of acupuncture compared with sham acupuncture (n = 189, weight mean difference, 3.09, 95% confidence intervals -0.04 to 6.23, P = 0.05) but marked heterogeneity was observed in this model (chi (2) = 8.32, P = 0.02, I (2) = 76%). One RCT compared the effects of electroacupuncture (EA) with hormone replacement therapy. Hormone therapy was more effective than EA. Another RCT compared acupuncture with venlafaxine and reported no significant intergroup difference. A further RCT compared acupuncture with applied relaxation and failed to show a significant intergroup difference. In conclusion, the evidence is not convincing to suggest acupuncture is an effective treatment of hot flash in patients with breast cancer. Further research is required to investigate whether there are specific effects of acupuncture for treating hot flash in patients with breast cancer.