The literature on pre-operative radiotherapy (RT) vs. post-operative RT in patients with advanced, resectable squamous cell carcinoma of the head and neck is reviewed and the theoretical arguments for and against the two different modalities discussed. It was possible to identify eleven reports published during the last four decades (1965-91) evaluating different aspects of pre- vs. post-operative RT given at comparable dose levels. Two reports were of prospective, randomised clinical studies and nine of retrospective comparisons. Together, the eleven studies comprised 1,358 patients (326 in prospective studies). The bulk of the evidence clearly suggests post-operative loco-regional control to be superior to pre-operative RT. However, this seems to be offset by the subsequent development of distant metastases or metachronous tumours.