Cigarette smoking is widely prevalent among individuals in treatment for drug or alcohol dependence; however, the treatment of nicotine addiction in this population has numerous obstacles at both programmatic and patient levels. Despite these difficulties, recent studies have demonstrated moderate success in implementing smoking cessation treatment in drug rehabilitation programs. The National Drug Abuse Treatment Clinical Trials Network sponsored a smoking cessation study in 13 community-based outpatient substance abuse rehabilitation programs across the country. The study evaluated the effectiveness of smoking cessation treatment provided as an adjunct to substance abuse treatment-as-usual. This report summarizes the practical and clinical experiences encountered at each of the study sites with regard to implementing the smoking cessation treatment intervention. Smoking behavior of the treatment clientele was assessed by anonymous survey at each site. In addition, sites were systematically characterized by using program review and assessment tools completed by the respective staff and program directors at the site. Survey and recruitment data indicated that cigarette smoking is more prevalent and that smoking cessation treatment is more feasible, in methadone maintenance treatment programs. Other factors associated with smoking behavior and with the recruitment of drug- and alcohol-dependent individuals into the smoking cessation treatment study are described.