During 1985 many drug abusers residing in Edinburgh were found to be infected with HIV. Consequently, an alternative counseling and screening clinic for testing for HIV antibodies was established for use by drug abusers. A total of 441 patients were counseled in the first year, and over 60 percent were either drug abusers or sexual contacts of drug abusers. One hundred and fourteen (26 percent) patients were positive for HIV antibodies, and 100 (88 percent) of these were current or former drug abusers. The HIV seropositivity rate in drug abusers was 52 percent, but was only 7 percent in their sexual contacts. Services were provided for these people as well as counseling before and after the test. The cost of this counseling service for the first year was 27,000 pounds sterling or 61.22 pounds sterling per patient. The unexpected mobility of 23 percent of the Edinburgh drug abusers, particularly to other areas of Great Britain, suggests that similar service should be set up elsewhere. 17 references. (Author abstract modified)