Background: Low-weighed mothers’ attitude towards the lack of their milk for breast feeding is one the most important causes of unsuccessful breast feeding. Meanwhile, prior investigators have raised controversies regarding the association between maternal BMI and infant’s growth. Thus, the present study was carried out on low- and moderate- weighed mothers and their infants to determine the association between the maternal BMI and infants’ growth during the first 4 months in Kashan in 1376-77.

Materials and methods: This cohort study was conducted on infants of low weighed mothers (BMI<19.8 as the case group) and infants of normal weighed mothers (19.8

Results: The study population included 75 cases and 75 controls with the mean birth weight of 3257.27±421 and 3286.2±455 gr. Their mean age was 5362.8±606.4 and 5497.8±621.27 gr after 2 months and 6793.2±682.4 and 7004±762.4 gr after 4 months, respectively (NS). We have not found any significant association in height, head and arm circumference between the two groups.

Conclusion: Low weight of mothers does not have any influence on physical infant’s growth. Further studies with bigger sample size and greater duration (the first 2 years) is strongly recommended.