Background and Objectives: To identify breast-specific factors and the role of tumor, treatment, and patient-related items in influencing patient opinion on cosmesis and satisfaction after breast-conserving therapy (BCT). Methods: Data from the randomized COBALT study was used. At 3, 12, and 36 months, 128 patients with T1-T2 breast cancer completed a questionnaire on breast-specific factors and overall cosmetic outcome and patient satisfaction, using a 4-point Likert scale. Results: There was a strong positive correlation between breast-specific factors, overall cosmetic outcome,and satisfaction at all time-points. Excellent/good cosmetic outcomes and satisfaction decreased during follow-up. A shift was noted in the degree of influence of the various breast-specific factors. At 3 years, symmetry factors such as size, shape, and nipple position largely determined a patient's opinion on the final cosmesis, followed by firmness. The risk of an unacceptable outcome was associated with young age and large excision volumes. Conclusion: A questionnaire including breast-specific questions provides important information on final cosmetic results and satisfaction after BCT. These outcomes can also be of great value as quality indicators and pre-operative counseling. The major influence of breast-specific factors on asymmetry underlines the importance of achieving an optimal excision volume at the initial procedure.