Three measures of body size (weight, height and obesity) were compared with other patient characteristics in 852 operable node-positive breast cancer patients (age, 25-74 yr) newly diagnosed in the USA. Weight and obesity were significantly associated with number of positive nodes. In postmenopausal women, weight and obesity were weakly associated with estrogen receptors. Observed weight and height distributions were compared with national averages and found to be highly aberrant in older women. There was an excess of tall women (.gtoreq. 65 inches) among the study group in all age groups. An excess of heavy women (.gtoreq. 140 lbs) among the study group was observed only in the 55-74 yr age group.