Breast reduction mammaplasty allows examination of specimens from a seemingly healthy population for the presence of proliferative breast disease. The authors reviewed the charts of all reduction mammaplasty patients of a single surgeon over 7.5 years for age, family history, mammographic results, unilateral or bilateral nature of the procedure, and final pathologic diagnosis. Of 182 patients, 168 had bilateral and 14 had unilateral breast reductions. Ages ranged from 16 to 79 years (average and median: 37 years and 35 years respectively). Fifty-seven patients (31%) were younger than 30 years, 53 patients (29%) were between the ages 30 years and 39 years, for a total of 110 patients (60%) younger than 40 years in this study. A total of 163 patients (89%) had a diagnosis of normal breast tissue. Nineteen patients (10%) had proliferative changes: 9 patients (5%) without atypia, 5 patients (3%) with atypia, 3 patients (2%) with sclerosing adenosis, and 1 patient each (0.5%) with papillomatosis and lobular carcinoma in situ. A total of 95% of patients with proliferative changes were older than 30 years. Women ages 30 to 39 years may be at higher risk (15%) of having proliferative changes than previously reported, and histologic examination of all reduction mammaplasties is recommended.