Diabetologists and diabetic patients were asked about their preferences for aspects of care which are considered of importance in relation to the quality of care. A questionnaire was constructed using the method of pairwise comparison in which respondents constantly had to chose between the statements in order to get a priority list. Adults with diabetes mellitus (Types 1 and 2) attending outpatient departments were asked to fill in the questionnaire. A response rate of 97% was recorded (n = 94). Diabetologists received a postal questionnaire and the response rate was 65% (n = 126). There was a reasonable agreement between both populations and 'effectiveness of care' was ranked the highest. However, the patients gave a significant higher ranking to 'continuity of care' and a lower ranking to 'efficiency'. Neither the age and sex of the patients nor the duration of the disease had any influence on their opinions. Patients who were treated with oral medication ranked 'information' higher than patients using insulin, but the difference was not significant. A lower level of education and having public-health insurance were associated with a higher preference for 'continuity'. No differences were found regarding age and sex within the diabetologist population.