We have shown that conditioned phenomena occur in a number of drug-related settings and that they can be reliably elicited and studied. Our recent work suggests that conditioned craving is an extremely prevalent, if poorly understood, response to drug-related stimuli and that it can occur independent of conditioned withdrawal responses. Our current extinction protocols are effective in reducing the conditioned responses to both opioid and cocaine-related test stimuli. How well this extinction training generalizes to the "real world," is, of course, the crucial clinical question. We are trying to maximize the generalization of extinction through use of realistic, individualized drug "reminders." The final clinical impact of these extinction procedures awaits completion of our ongoing treatment/outcome studies in abstinent opioid and cocaine abusers.