The 1996 Agency for Health Care Policy and Research's Smoking Cessation Clinical Practice Guideline provides a strong empirical foundation for effective smoking cessation interventions in primary care. Screening all patients for tobacco use status at each clinic visit and providing at least brief cessation advice to all smokers can have a significant system-wide effect. Adding additional treatment components, such as pharmacotherapy, problem solving, and social support, can increase quit rates by twofold or more. Information on effective and ineffective treatment components is provided, along with new information published after the release of the Guideline.