OBJECTIVES: To assess the knowledge of early childhood caries and to examine the current preventive oral health-related practices and training among Canadian paediatricians and family physicians who provide primary care to children younger than three years. METHODS: A cross-sectional, self-administered survey was mailed to a random sample of 1928 paediatricians and family physicians. RESULTS: A total of 1044 physicians met the study eligibility criteria, and of those, 537 returned completed surveys, resulting in an overall response rate of 51.4% (237 paediatricians and 300 family physicians). Six questions assessed knowledge of early childhood caries; only 1.8% of paediatricians and 0.7% of family physicians answered all of these questions correctly. In total, 73.9% of paediatricians and 52.4% of family physicians reported visually inspecting children’s teeth; 60.4% and 44.6%, respectively, reported counselling parents or caregivers regarding teething and dental care; 53.2% and 25.6%, respectively, reported assessing children’s risk of developing tooth decay; and 17.9% and 22.3%, respectively, reported receiving no oral health training in medical school or residency. Respondents who felt confident and knowledgeable and who considered their role in promoting oral health as “very important” were significantly more likely to carry out oral health-related practices. CONCLUSION: Although the majority of paediatricians and family physicians reported including aspects of oral health in children’s well visits, a reported lack of dental knowledge and training appeared to pose barriers, limiting these physicians from playing a more active role in promoting the oral health of children in their practices.