Background: Dental caries (decay) is an international public health challenge, especially amongst young children. Early Childhood Caries is a rapidly progressing disease leading to severe pain, anxiety, sepsis and sleep loss, and is a major health problem particularly for disadvantaged populations. There is currently a lack of research exploring the interactions between risk and protective factors in the development of early childhood caries, in particular the effects of infant feeding practises. Methods/Design: This is an observational cohort study and involves the recruitment of a birth cohort from disadvantaged communities in South Western Sydney. Mothers will be invited to join the study soon after the birth of their child at the time of the first home visit by Child and Family Health Nurses. Data on feeding practices and dental health behaviours will be gathered utilizing a telephone interview at 4, 8 and 12 months, and thereafter at 6 monthly intervals until the child is aged 5 years. Information collected will include a) initiation and duration of breastfeeding, b) introduction of solid food, c) intake of cariogenic and non-cariogenic foods, d) fluoride exposure, and e) oral hygiene practices. Children will have a dental and anthropometric examination at 2 and 5 years of age and sssssthe main outcome measures will be oral health quality of life, caries prevalence and caries incidence. Discussion: This study will provide evidence of the association of early childhood feeding practices and the oral health of preschool children. In addition, information will be collected on breastfeeding practices and the oral health concerns of mothers living in disadvantaged areas in South Western Sydney.