Background and Aims: Improper feeding is one of the most important etiologic factors in early childhood caries (ECC). In some clinical trials, breast feeding (BF) is mentioned as a causing factor in ECC. Results in this topic are different or even controversial. It is vital that all general advices given out are consistent with general health education messages. The aim of this study was to conduct a systematic review on the relationship between breast feeding and early childhood caries. 

Materials and Methods: Articles, guidelines, related books, and specific databases such as SID, PubMed, Scirus, Elsevier, American Association of Pediatric Dentistry (AAPD), American Association of Pediatrics (AAP) and American Dental Association (ADA) were searched for related topics cited since 1990. Early childhood caries definition, breast feeding and other variables such as sample size, study location and study design were analyzed.

Results: According to data analysis, there was a lack of methodological consistency and inconsistent definitions of ECC and BF in the literature making it difficult to draw conclusions. Results about relationship between prolonged BF and ECC were inconclusive. There was a positive relationship between nocturnal BF and ECC. A history of BF did not have any effect on the caries incidence.

Conclusion: Because of the role of breast feeding in children^'s health, it is important to inform the parents about the possibility of dental caries due to nocturnal breast feeding.