While WHO headquarters have a long tradition in quality assurance in specific areas such as clinical laboratories and radiology, quality assurance of personal health services was not introduced until the beginning of the 1980s by the WHO Regional Office for Europe. This paper describes the rationale, components, objectives and activities of the WHO programme entitled "Model health care programmes and quality assurance of health services" from 1983 to 1988. The last section of the paper looks at the signs of success, i.e. changes on the quality assurance scene in Europe that may have resulted from WHO's work. As no other major international organization was interested in the quality of care, WHO focused on two qualitative aspects: the appropriate combination of services in the care of patients with a given health problem (model health care programmes) and the quality of service (quality assurance). The programme sets objectives for both Member States and WHO: Member States are expected to establish policies and mechanisms for systematic quality assurance, WHO to clarify and promote the concept and develop methods and models as well as train health professionals. Publications, working groups, training courses and international cooperation have aimed at reaching these objectives. The possible signs of success include changing attitudes, emergence of a critical mass of health professionals interested in quality assurance and laws on, and national plans including, quality assurance.