Smoking cessation counseling by practitioners occurs at low rates in spite of strong evidence that counseling increases quit rates and reduces patient mortality. In a preliminary study, 1060 New York State physicians completed a survey concerning use of the Agency for Health Care Policy and Research (AHCPR) Guidelines, perceived autonomy and perceived competence for counseling, perceived autonomy support from insurers, and barriers to counseling. Considered together, perceived autonomy, perceived competence and perceived autonomy support predicted time devoted to counseling and use of the AHCPR guidelines. The primary, longitudinal study of 220 health care practitioners who attended a smoking cessation workshop predicted change in the practitioners' perceived autonomy and perceived competence for counseling as a function of the degree to which they experienced the workshop instructor as autonomy-supportive. In turn, change in perceived autonomy predicted change in time spent counseling and change in use of the AHCPR guidelines.