The characteristics of clients discharged from federally funded treatment facilities reporting to CODAP [Client Oriented Data Acquisition Process] were analyzed in terms of several variables: the reasons for discharge (treatment completed, transfer or referral or treatment not completed), the primary drug of abuse at admission (opiates and nonopiates) and the number of prior treatment experiences. Two independent replications using data for 2 consecutive quarters found that the likelihood of completing treatment decreases as the number of prior treatment experiences increases. This relationship applied to both opiate and nonopiate users. Although large differences existed in completion rates between opiate and nonopiate users without prior treatment experience, only small differences existed between opiate and nonopiate users who had prior treatment. The largest difference in treatment outcome occurred between those with no prior treatment and those who were treated before. Having 1 or more prior treatment experiences does not seem to have a major impact on the probability of completing treatment.