A postal survey of 4066 men and women aged between 16 and 64 years was carried out in a general practice in Oxfordshire which had a patient participation group, established in 1972. The aim of the survey was to ascertain the knowledge and use of the group among adults aged 16-64 years. The adjusted response rate was 73%. Despite the length of the group's existence only 45% of these patients were aware of it and only 7% had ever attended a meeting. Awareness of the group and sometime attendance were significantly less in men, patients aged between 16 and 29 years, those in social classes 4 and 5, single people and those who smoked. Patients who consulted more than four times per year were more likely to be aware of the group than less frequent consulters. The possible reasons for the unrepresentative nature of the patients attending the group are discussed, together with implications for practice policies and development. Various strategies for making the group more representative are proposed, including advertising within the practice and elsewhere, and the formation of special interest groups for patients with defined medical and social needs, in the hope that this will make the concept of patient participation more relevant.