BACKGROUND: Despite the fact that it is largely preventable, dental caries (decay) remains one of the most common chronic diseases of early childhood. Dental decay in young children frequently leads to pain and infection necessitating hospitalization for dental extractions under general anaesthesia. Dental problems in early childhood have been shown to be predictive of not only future dental problems but also on growth and cognitive development by interfering with comfort nutrition, concentration and school participation. OBJECTIVE: To review the current evidence base in relation to the aetiology and prevention of dental caries in preschool-aged children. METHODS: A search of MEDLINE, CINALH and Cochrane electronic databases was conducted using a search strategy which restricted the search to randomized controlled trials, meta-analyses, clinical trials, systematic reviews and other quasi-experimental designs. The retrieved studies were then limited to articles including children aged 5 years and under and published in English. The evidence of effectiveness was then summarized by the authors. CONCLUSIONS: The review highlighted the complex aetiology of early childhood caries (ECC). Contemporary evidence suggests that potentially effective interventions should occur in the first 2 years of a child's life. Dental attendance before the age of 2 years is uncommon; however, contact with other health professionals is high. Primary care providers who have contact with children well before the age of the first dental visit may be well placed to offer anticipatory advice to reduce the incidence of ECC.