OBJECTIVE: We describe the methods used to trace and recruit a cohort (including injecting drug users) 25 years after admission to hospital in Melbourne with hepatitis. METHODS: Information recorded in the original medical record was used for tracing purposes. Subjects were located using the electoral roll, CD-ROM telephone directory, the Health Insurance Commission database, Hepatitis Foundation newsletters, advertising and features in the press and local radio. Other approaches included contacting local medical officer or next of kin from the original admission, and the National Death Registry. RESULTS: Tracing was undertaken on all members of the cohort; two-thirds were located. Methods were applied sequentially and 36% were found by CD-ROM telephone directory and the electoral roll, 33% from Health Insurance records, 15% by letter to last known address, 10% from contact of original next of kin, 3% from radio publicity and 1% from media advertisements. Of those who were located, 85% participated in the study. CONCLUSIONS: Accurate ascertainment of birth date and full name from original case records was essential for tracing purposes. Use of Health Insurance records and CD-ROM telephone directory and the electoral roll were the most successful means of locating subjects while newspaper advertising was non-productive and expensive. History of IDU was the major association with failure to trace and unwillingness to enrol, but despite this tracing and recruitment was high in this group. The high participation rate in those located appears to be due to the experience of the staff member making the initial contact.