To determine if body weight and serum cholesterol are associated with advanced primary breast cancer, the authors compared levels of both by TNM stage and estrogen receptor protein (ERP) concentration in a population of 148 premenopausal and 167 postmenopausal white women with histologically confirmed Stage I, II, and IIIa breast cancer. The women were admitted to Memorial Sloan-Kettering Cancer Center (MSKCC) in New York City between 1982 and 1984. Overweight, whether measured as body weight in pounds, Quetelet index, or body surface area, was not found to be associated with TNM tumor stage, tumor size, extent of axillary node disease, or ERP concentration at mastectomy. Elevated serum cholesterol, either alone or in combination with overweight, also showed no association. When assessed in light of earlier studies, the study findings suggest that if overweight, as defined in this study, and/or elevated serum cholesterol do influence early breast cancer recurrence, they do so other than through an association with advanced primary disease. Suggestions for future research are proposed.