Objective: To assess: (1) physicians' knowledge and clinical confidence regarding problematic substance use in pregnancy compared to folic acid, and (2) physicians' desire for education in this area and their preferred learning modalities tools. Design: Self-administered survey. Setting: "Family Medicine Forum 2004" in Toronto, Canada. Participants: Physicians attending "Family Medicine Forum 2004" in Toronto who provide antenatal care. Main Outcome Measures: Knowledge of folic acid, smoking and alcohol in pregnancy. Clinical confidence and interest in resources regarding problematic substance use in pregnancy. Results: Sixty-six surveys completed. Physicians answered 92.3% of folic acid questions correctly, compared to 82.0% for nicotine and 57.1% for alcohol. Scores were higher on questions about effects of nicotine and alcohol use in pregnancy than on questions about treatment options. A perceived inability to influence clinical outcomes and a lack of professional resources regarding substance use in pregnancy were also identified. Physicians were interested in learning more about problematic substance use in pregnancy, particularly from continuing medical education events, websites and pocket cards. Conclusion: Participants' level of knowledge regarding substance use in pregnancy was significantly lower than their knowledge of folic acid, as was their clinical confidence. This lack of knowledge was not attributable to disinterest and clearly more educational resources are needed to address this topic. (Contains 3 figures and 4 tables.)