Health-related quality of life (HRQOL) is becoming an increasingly more important primary or secondary end point of clinical studies. Patients and their self help organizations demand a greater regard to their subjective experience of their disease and its treatment. Cost-effectiveness analyses measuring quality-adjusted life years are becoming more and more decisive in health politics. Therefore it is important for gastroenterologists to know the concepts and methods of HRQOL-measurement. The present article discusses the definitions of (health-related) quality of life and reviews generic- and disease-specific quality of life instruments in gastroenterology including quality criteria. Rules for the adaptation of Anglo-American questionnaires into German-speaking countries are pointed out. Finally the limitations of the concepts of HRQUOL and its measurement are discussed.