The objective was to assess the effectiveness of a smoking cessation educational program on pediatric residents' counseling. Residents were randomly selected to receive the intervention. Residents who were trained were compared to untrained residents. Self-reported surveys and patient chart reviews were used. Measures included changes in self-reported knowledge, attitudes and behaviors of residents, and differences in chart documentation and caretaker-reported physician counseling behaviors. The intervention was multidimensional including a didactic presentation, a problem-solving session, clinic reminders, and provision of patient education materials. Results showed that residents who were trained were more likely to ask about tobacco use in their patients' households. They were also more likely to advise caretakers to cut down on or to quit smoking, to help set a quit date, and to follow up on the advice given at a subsequent visit. Trained residents were more likely to record a history of passive tobacco exposure in the medical record. These residents also reported improved confidence in their counseling skills and documented that they had done such counseling more often than did untrained residents. Caretakers of pediatric patients who smoke seen by intervention residents were more likely to report that they had received tobacco counseling. Following this intervention, pediatric residents significantly improved their behaviors, attitudes, and confidence in providing smoking cessation counseling to parents of their pediatric patients.