According to controlled trial results, adjuvant radiotherapy associated with radical surgery has significantly decreased local recurrences of breast tumours, but with no effects on survival. Nowadays, in controlled trials, the advantages of associating radiotherapy with surgery and adjuvant chemotherapy are not clear. A non-significant trend towards better control of local disease is observed in some trials, mainly in locally advanced disease. In most of the other trials no benefit has been found. Although some detrimental effects have been observed when adjuvant chemotherapy was delayed or reduced by radiotherapy, on the whole radiotherapy does not appear to have any harmful effects on final results.