OBJECTIVE: Quality of life (QOL) is becoming an accepted endpoint in cancer clinical trials. However, reports suggest that fewer than 10% of clinical trials include QOL assessment, it is believed that such reports may be biased by time lag. This paper examines the extent of QOL studies that are conducted within one of the largest academic cancer clinical trial organizations in Europe. METHOD: Examination of all clinical trials conducted by the EORTC (between 1990 to 2000) was undertaken by reviewing data from databases, records and publications. Trials were systematically selected if they involved any aspect of QOL assessment. The protocols were then evaluated using criteria that evaluated the quality of trial designs and methodology employed. RESULTS: In total, 112 clinical trials involving over 10,000 patients were identified as having a QOL component. All trials involved multinational patient recruitment, with the highest recruitment from The Netherlands, France and Germany, lowest from Malta, Estonia and Slovakia. Approximately 25 disease groups have been actively recruiting, with patients being from disease groups of genito-urinary, breast and lung cancers. A clear linear trend was noted, with increasing numbers of clinical trials involving QOL components over this period. Of these trials, 74 studies were Phase III, 15 Phase II and the remainder were feasibility studies. Presently, 45 trials are ongoing, 19 almost ready for data analysis, 15 published and 10 being analyzed. In the last year, 30 studies involving QOL assessment have been submitted for research, suggesting that QOL is a highly important endpoint in trials throughout Europe. CONCLUSION: While a decade ago QOL was not a major component of EORTC clinical trials, it is now highly integrated into trials, almost a standard secondary endpoint. In the European context, this suggests that clinicians and researchers are increasingly seeing the importance of patient-based outcome assessment methods.