The main objective of this study was to evaluate the advantages and shortcomings of a new kind of registration of illicit drug users in Flanders, Belgium. Data about the profile of drug users who have come into contact with the law were collected by examining the records kept by the District Courts. On the one hand, published data on illicit drug users in Flanders are scarce. On the other hand, a lot of unused judicial information is available. All District Courts in Flanders (n=13) and Brussels (n=1) participated in the study. The data show that a simple registration of verbalised drug users with a short questionnaire can provide useful information for prevention campaigns and police investigation and shows the importance of prevention programmes starting at school. Notwithstanding some shortcomings, the illicit drug users' registration system by means of judicial data in Flanders forms a solid basis upon which an integrated registration of illicit drug use can be built.