Background: This study monitors a syringe exchange program (Malmö, Sweden), in which all visits and exchanges are registered anonymously, although some services e.g. HIV-tests and vaccinations need identification. Methods: Two datasets are used. a) About 500 visitors were interviewed on childhood as well as present social situation, health, drug use, risk behaviors, social network and treatment experiences. Their visits as well as amount and types of services used were monitored during 40 months. b) All visits between 1989 - 2003 (177699 visits, 3660 users) were continuously registered, including services used. Results: The visitors (mean age 35.5 ys, 71 % men) had used drugs 23 years and injected 16 years. Prevalence of HIV was low (2.3 %) but frequent on hepatitis B and C (61 and 86 %, respectively). The number of users who shared needles �last year� was 37 % and �last month� 19 %. Number of visits varied from 1 to 616, and the average visitor came once in two months. They collected 63 syringes per year (mean) and gave 44 (70 %) in return. Most visitors (86 %) used additional services, and in more than 40 % of the visits. Nearly all (98.5 %) tested for HIV; 36 % had physical examination, and 22 % other health care, 20 % met the counsellor and 27 % vaccinated against Hepatitis B. This had a dramatic effect in reducing the relative risk for such infection (odds ratio 0,004). The second dataset is currently being analyzed. The presentation will include various patterns of program utilization over time. Conclusions: Utilization of the services varies to a great extent. Few visitors make the majority of visits. Most users do not visit frequently enough to supply their need of clean needles. Hence, there is still a high incidence of hepatitis. But the large majority seems to use the additional services. The development over time for diverse groups of visitors will be further explored in the paper.