Objective: Birth weight is one of the most important ,simplest and common determinations for assessments infants status in each country. this study has been designed to investigate the articles that published in its prevalence and related factors.

Materials & Methods: This study is a review articles that focuses on the prevalence and association factors whit low birth weight in the last 10 years. Articles were searched in 6 data base (PubMed ،Iranmedex ،SID، Irandoc، Scholargoogle، magiran) ، the refrences of each articles with the use of keywords : low birth weight ,infant mortality ,risk factors,related factors, prevalence and social determinants of health.

Results: Overall, 36 articles were assess,14 article reported low birth weight related factors and 22 articles reported prervalence and its related factors, that in 70% prevalence was (5-12%) and in 5 articles prevalence were reported( 13-19/1%).association factors that were reported include demographic ,socioeconomic ,lifestyle factors and social support. demographic factors had the most relationship whit low birth weight.

Conclusion: Although there was some different in their studies (differences in the definition of low birth weight, non or low reporting , low sample size, etc),the overall prevalence of low birth weight is relatively high in Iran so we suggest education, increasing prenatal care particularly for high –risk age groups that can be useful for reducing the consequences of this adverse pregnancy outcome