148 consecutive patients treated by two different types of conservative surgery were objectively and subjectively evaluated for cosmetic outcome. In 73 patients, tumorectomy, axillary dissection, external radiotherapy (45 Gy) plus iridium implant (15 Gy) were performed, while in the other group of 73 patients a more extensive surgical approach was carried out: quadrantectomy, axillary dissection plus external radiotherapy (50 + 10 Gy). The appearance of the patients' breasts was analysed for symmetry by computer, and differences in symmetry were correlated with tumour location and breast size. A subjective assessment was given by a 3-member panel and the results were correlated with objective measurements. In addition, patients were asked to fill out a self-assessment questionnaire on the aesthetic result of the operated breast. Better results were generally noted in the group of patients treated by more conservative surgery. Substantial differences in the aesthetic outcome were noted between the patient's own evaluation, the computer's measurement of symmetry and the assessment of the panel of observers.