Minimal intervention strategies to decrease long-term benzodiazepine use have not yet been evaluated in large primary care based studies with a blinded control condition and a long follow-up period. The purpose of this study was to assess the effects of a letter with a discontinuation advice sent to long-term benzodiazepine users in family practice followed by an evaluation consultation offer. The experimental group consisted of 2425 long-term benzodiazepine users, 1707 of whom were addressed by a discontinuation letter and an evaluation consultation offer. The control group consisted of 1821 long-term users. Primary endpoints were the number of prescribed daily dosages (PDD) and the percentage of subjects without prescription (quitters). At 21 months a reduction in benzodiazepine prescription of 26% was observed in the experimental group, versus 9% in the control group (PDD difference=12.5; 95%-ci: 8.2-16.8). In the experimental group 13% and in the control group 5% of the study completers were benzodiazepine prescription free through the full follow-up period (RR=2.6; 95%-ci: 2.0-3.4). The percentage of quitters at short-term (6 months) was 24% in the experimental group versus 12% in the control group (RR=2.1; 95%-ci: 1.8-2.4). It is concluded that this intervention strategy steadily reduces long-term benzodiazepine use in family practice.