The European Organization for Research and Treatment of Cancer (EORTC) has a long history in the development of quality assurance, in particular in radio- and chemotherapy. Quality assurance in surgical oncology is considered to be more complicated, because it is a multistep procedure depending on the individual. Because of the growing importance of the quality of surgical intervention in the multi-modality treatment approach of most cancers, the EORTC recently decided to investigate the current status of quality assurance programmes, both outside and within, the EORTC. The review of EORTC involvement in this area has been conducted on the basis of interviews with subcommittee chairmen and Data Center teams of the EORTC clinical research groups. In addition, clinical trial protocols, case report forms (CRFs) and publications by the EORTC groups related to this field were considered as possible sources of information. Several methods have been used or are currently under investigation to ensure the quality of surgery within clinical trials. These include review of reported data, standardisation of surgery and pathology forms, training sessions and site visits. However, there has been no attempt to harmonise these initiatives across the different medical specialties. The EORTC will have to address this problem within its short-term scientific strategy.