Although environmental tobacco smoke is a common trigger for asthma exacerbations in children, pediatricians infrequently counsel parents who smoke to quit. High physician self-efficacy, or self-confidence, in the ability to counsel parents about smoking cessation is associated with increased physician screening and counseling on this topic. However, it is not clear which factors are associated with high physician self-efficacy for counseling, such as previous training in smoking-cessation counseling or number of years in pediatric practice. To identify factors associated with high levels of physician self-efficacy for 4 skills associated with smoking-cessation counseling. Cross-sectional survey. A national random sample of 829 primary care pediatricians. The response rate was 55% (457 of 829). The percentage of physicians with high levels of self-efficacy for screening parents and screening patients to identify smokers was 87% and 84%, respectively. The percentage of physicians with high levels of self-efficacy for counseling parents and patients was 59% for both groups. The presence of previous training in smoking-cessation counseling was associated with high levels of self-efficacy for all 4 skills including inquiring about an asthma patient's smoking status (odds ratio [OR]: 3.91; 95% confidence interval [CI]: 1.63, 9.37); inquiring about a parent's smoking status (OR: 2.51; 95% CI: 1.09, 5.75); counseling a patient to quit smoking (OR: 5.30; 95% CI: 3.02, 9.31); and counseling a parent to quit (OR: 4.96; 95% CI: 2.85, 8.61). Years since completion of residency were not associated with high self-efficacy. These findings suggest that formal training in smoking cessation has a significant impact on physician self-efficacy related to smoking cessation throughout a physician's career.