Between January 1975 and December 1984, 239 patients after breast conserving surgery were referred to the University Clinic for Radiotherapy and Radiobiology of Vienna. Of these patients 214 were available for analysis with regard to loco-regional control and cosmetic outcome. The breast received supervoltage irradiation from two tangential fields, in 82% with a tumor dose of 50 Gy and in 15% 50 to 60 Gy. In addition 70% of the patients received a boost dose with 7.5 to 15 MeV electrons to the tumor bed and the scar. The overall local failure rate was 10.2%. For patients with T1,2 and negative axillary nodes or less than four positive lymph nodes (N = 160) a recurrence rate of 7.1% was observed. Factors correlated to a higher local recurrence rate were in this retrospective study axillary status (greater than 3 positive lymph nodes), histopathologic grade (G III), absence of clear margin after surgery and absence of additional electron boost.