The risk and prognosis of patients with carcinoma of the breast exposed to postmenopausal hormones are controversial. Carcinoma of the breast from 35 postmenopausal women who had taken hormones were compared with carcinomas from age and histologic matched postmenopausal women who had never taken hormones. Hormone users averaged 1.1 fewer pregnancies (p<0.005) and 1.4 fewer live births (p<0.0005). In addition, the carcinomas had significantly lower S-phase fractions (5.36 versus 6.77, p>0.01) and less nodal involvement (1.2 versus 1.9, p<0.0005). Estrogen and progesterone receptor content, ploidy and deoxyribonucleic acid index were comparable in both groups. These results indicate that hormone users present with slower growing tumors of earlier stage than nonusers, possibly resulting in improved prognosis.