In recent years, the population and professional people have become increasingly aware of the need for a more systematic assessment of quality in health service. On basis of this, a Danish workshop was held in 1988 concerning scientific methods of assessing quality in the health sector. This review provides an introduction to the expressions "assessment of quality" and "insurance of quality" in the health sector. The main points from the workshop are quoted and concrete examples of assessment of quality in the Danish health service are given. It is concluded that after a couple of decades in which health political analyses and decisions have primarily been concentrated on productivity and efficacy, we may consider insurance of quality as an instrument for decision-making in the current adjustment of the health service to the changes in knowledge, attitudes and technology.