Introducing a Quality Assurance methodology appears particularly useful in Radiation Oncology due to the complexity of the procedures involved and the heterogeneity of the standards adopted, if any, in the great majority of the Centers. There are two possible ways of evaluating quality in the Health Environment: a formal, Institutional certification, or a voluntary one obtained through a mechanism of peer review. The European Society for Therapeutic Radiology and Oncology (ESTRO) started in 1994 with the publication of a methodological Report intended to be adopted by the individual national Societies, and this paper is an invitation to do it.