One hundred seventy elderly women with stage II breast cancer, stratified on the basis of the number of positive axillary nodes and estrogen receptor status, were randomly assigned to receive tamoxifen or placebo for 24 months in a prospective, double-blind, adjuvant trial. The median age was 71 years with a range from 65 to 84 years. The overall percentage of patients disease-free at 4 years was 76% for those given tamoxifen and 52% for those given placebo (p = 0.0004). Benefit was seen in all subgroups of patients treated with tamoxifen. Two years of tamoxifen therapy represents an effective postoperative adjuvant treatment for elderly women with stage II breast cancer, resulting in improved time to relapse, statistically fewer distant first recurrences, and minimal toxicity. No improvement in overall survival has been seen yet.