Background and Objective: Child weight is considered as one of the most appropriate criteria for determining the nutritional status of the children particularly prior to 24 months of age. There is an association between duration of breastfeeding and child weight via which childhood and even adult obesity can be predicted. Regarding the importance of breastfeeding and its critical role in future health of children, the present research was carried out to investigate the association between the duration of exclusive breastfeeding and the weight of 24- month-old children in Zanjan province.

Materials and Methods: This cross-sectional research was carried out using the registered data from 24 months old children records in rural/ urban health centers of Zanjan province. The sampling included all records of neonates born from 2010 to 2012 which were selected using a multi-stage cluster sampling method. Data were assessed by ordinal regression with the Proportional odds model and chi-square test. Stata12 was used for data analysis.

Results: Of 8456 children with the age of 24 months, 4146 (49%) were female. The mean age of the mothers was 27.1±5.4 years. The mean duration of breastfeeding and exclusive breastfeeding with related standard deviation were 20.3±5.8 and 4.7±1.4 months, respectively. The mean and standard error concerning 24-month- old children’s weight was 11939±13.2 grams. There was an inverse relationship between the duration of breastfeeding and exclusive breastfeeding with 24-month-old children’s weight (p<0.001).

Conclusion: This study elucidates that continuation of breastfeeding until 24 months of age may prevent child obesity. Therefore, exclusive breastfeeding encouragement and the continued breastfeeding until 24 months are critically recommended.