The long-term prognosis in 233 primary breast cancer patients, most of whom had received ovarian irradiation, has been related to the estrogen-receptor status of the primary tumors. The median observation time was 9 years. The receptor status did influence disease-free interval and survival only in patients having metastases in axillary nodes. Thus, in the postmenopausal patients with axillary metastases, the disease-free interval and survival time were longer in receptor-positive than in receptor-negative patients during the first few years of observation. However, this difference disappeared in the course of the subsequent years. In the premenopausal women with axillary metastases the receptor status did not influence the short-term prognosis, and, unexpectedly, seemed to affect adversely the long-term prognosis. It is concluded that the long-term prognosis is no better in breast cancer patients having estrogen receptors in their primary tumors than in those with receptor-negative tumors.