One-hundred and nine injecting drug users entering a methadone detoxification programme underwent HIV antibody test counselling. Approximately 80% of men and women were concerned because of sharing injection equipment ('works') in the previous year, although other reasons for considering an HIV antibody test, such as sexual contact with drug users and concern for sexual partners, was also given. Two-thirds of both men and women decided to be tested. Reasons for declining or deferring an HIV antibody test included an inability to cope with a positive result, recent sharing of 'works', and intoxication with drugs or alcohol at the time of counselling. Of the 74 clients tested, two were HIV antibody positive. Only 55% of clients reattended for results. Testing drug users for evidence of HIV infection requires careful pre-test counselling and adequate support should be readily available when results are given.