Abstract
The present study was conducted as an evaluation of a two-year pilot program started in 1998 in the Netherlands to provide free hepatitis B vaccination targeted at drug users (DUs). In order to identify which demographic and social-cognitive factors predict vaccination uptake, written questionnaires were distributed in three pilot regions (Amsterdam, Tiel, and Maastricht) amongst all DUs that were invited to participate in the program during a 2-month period.