A battery of objective measurements of cosmetic outcome was performed on 114 patients who had been treated by breast-preservation techniques for breast cancer. Cosmetic breast retraction, as determined by Breast Retraction Assessment (BRA) measurements, was significantly greater in patients who underwent extensive primary tumor resection, were more than 60 years old, weighed more than 150 lbs, or had a primary tumor in an upper breast quadrant. While use of a local RT boost, per se, was not a significant factor, those patients with high dose and/or large volume local boosts more frequently had marked retraction. Breast telangiectasia and depigmentation (T/D) was related to use of a local RT boost, patient age greater than 60 years, and use of separate nodal RT fields. Breast T/D was significantly more frequent with use of electron beam local RT boost which delivered a boost skin dose exceeding 1600 cGy. Objective quantitative assessments, such as BRA and T/D area measurements, provide data to determine factors related to each type of cosmetic change and thus provide guidelines for optimizing cosmetic outcome. Limiting the extent of primary tumor resection may minimize the amount of breast retraction. Omitting the local RT boost, particularly large volume, high dose boosts, may reduce the frequency of marked cosmetic retraction and skin T/D.