Data from a smoking cessation program were analyzed to identify the variables that best predicted posttreatment abstinence. Nonsmoking immediately following treatment was predicted by lower daily pretreatment intake of nicotine and total particulate matter (TPM), as well as higher score on the "handling" scale of the "Why Do You Smoke" scale. Abstinence at any time in the 6 months following treatment was also predicted by lower pretreatment nicotine and TPM intake; other predictors were lower scores on the "craving" scale, greater number of weeks spent participating in the program, citing reasons for wanting to quit smoking other than to overcome an addiction, and lower self-rated craving for cigarettes. Abstinence was not predicted by subjects' adherence to the treatment rules calling for changing the times, occasions and feelings that are associated with the heaviest smoking. Daily cigarette consumption dropped during treatment at similar rates for the smokers who would eventually be abstinent and those who would not. These results replicate the finding that a behavioral self-control program can bring about a reduction in smoking in many smokers, though relatively few actually quit smoking. Also, smokers who find the manipulations involved in smoking to be rewarding are more likely to be abstinent, at least temporarily, following a behaviorally oriented program than are smokers who are most rewarded by the self-administration of nicotine. Smoking cessation programs might benefit by tailoring treatment to such pretreatment subject characteristics.