A total of 266 recurrence-free breast cancer patients from the randomized DBCG-82TM breast conservation trial were called in for a follow-up investigation to study the impact of surgical and radiation treatment factors on the cosmetic and functional outcome after breast conservation. The patients were interviewed and examined after a median follow-up time of 6.6 years, and 194 of them (73%) regarded the cosmetic result as excellent or good. Morbidity assessments showed that breast fibrosis, skin telangiectasia, and breast retraction were significantly associated with a less satisfactory cosmetic result. On univariate analysis, it was found that treatment with a direct anterior electron field produced more morbidity and inferior cosmetic outcomes compared with tangential photon treatment, while increasing breast size was associated with increased breast retraction and breast fibrosis. Treatment characteristics that emerged as independent prognostic factors of a poor cosmetic outcome on multivariate analysis were the use of a direct anterior electron field (OR = 2.15, CI 1.25-3.70) and adjuvant systemic therapy (OR = 2.13, 1.22-3.71). A significant but relatively low level of concordance was found between the patients' and the clinician's evaluations of cosmetic results but self-assessments of breast morbidity and psychological distress were significantly related to the observed treatment-induced side effects after breast-conserving treatment, indicating that subjective perceptions and observations as reported by the patients are relevant for the identification of treatment factors that impact on normal tissue reactions.