Cue exposure has been used successfully in the treatment of neurotic disorders. Its application to the treatment of drug dependence is founded on the premise that craving for drugs can become classically conditioned to internal and external drug-related cues and that such conditioned craving responses play an important part in relapse to drug use. This article reviews the theoretical background for the use of cue exposure, research on cue reactivity in samples of drug-dependent persons and the role of cue reactivity in relapse. What evidence exists on the clinical effectiveness of cue exposure is reviewed in some detail and a number of clinical issues relating to its practical application are discussed. It is concluded that controlled trials of the effectiveness of cue exposure treatment for drug dependence should be implemented without further delay.