During 1985 many drug abusers who lived in Edinburgh were found to be infected with the human immunodeficiency virus (HIV). As a result an alternative counselling and screening clinic for testing for antibodies to HIV was established for use by drug abusers. Four hundred and forty one patients were counselled in the first year, and over 60% were either drug abusers or their sexual contacts. One hundred and fourteen (26%) patients were positive for HIV antibody, and 100 (88%) ofthese were current or former drug abusers. The HIV seropositivity rate in drug abusers was 52% but was only 7% in their sexual contacts. Services were provided for these people as well as counselling before and after the test. The cost of this counselling service for the first year was £27 000 or £61.22 per patient.The unexpected mobility of 23% of the Edinburgh drug abusers, particularly to other areas of Britain, suggests that similar services need to be set up elsewhere.City Hospital, Edinburgh EH10 5SB R P BRETTLE, FRCP, consultant physician, infectious disease unit K BISSET, MB, CHB, medical officer, city screening clinic S BURNS, MB, CHB, senior registrar and counsellor, regional virus laboratory and city screening clinic J DAVIDSON, MB, CHB, medical officer, city screening clinic S J DAVIDSON, SRN, SCM, counsellor, city screening clinic J M N GRAY, RGN, SCM, counsellor, city screening clinic J M INGLIS, MRCPATH, top grade virologist, regional virus laboratory J S LEES, MB, CHB, medical officer, city screening clinic J MOK, MD, MRCP, consultant, community child health Correspondence to: Dr Brettle.