Background: Post-operative radiotherapy is an effective strategy to decrease the risk for loco-regional recurrence in breast cancer. However, some patients display signs of radioresistance. Biomarkers predicting radiotherapy response would be of valuable importance. Studies propose a role for Met in radioresistance, in vitro experiments show that Met expression is altered after radiation.In this study, it was aimed to determine MET copy number, Met and HGF expression, and phosphorylated Met in breast cancers to elucidate Met’s role in radiotherapy response. Patients and Methods: MET copy number was determined by qPCR in 171 tumours from post-menopausal patients randomised to receive either chemo- or radiotherapy. Met, activated Met and HGF expression was determined by immunohistochemistry in 228 tumours of pre-menopausal patients, likewise randomised to receive either chemo- or radiotherapy. Results: Increased MET copy number was detected in 34% of the tumours. High expression of Met, pMet and HGF was found in 33%, 28% and 62% of the tumours, respectively. Low MET copy number predicted better response to radiotherapy, compared with an increased number of MET copies. Patients with tumours bearing 1 or 2 MET copiesshowed a significant better response to radiotherapy than chemotherapy. Similar results were obtained with patients with low versus high expression of Met in the cell membrane. Contrary, this study shows favourable response towards radiotherapy in tumours with high pMet and/or HGF expression. Conclusion: Met overexpression and pMet show contrasting roles regarding radiotherapy response and more research is needed to understand the role of activated Met.