Background and Objective: Child obesity is increased in developing countries. This study assessed the prevalence of obesity on children which are exclusively on breast feeding and its duration among children aged 24-59 months in Bandar Turkmen district Northern, Iran.

Materials and Methods: In this descriptive- analytical study, 343 in children aged 24-59 months were selected with stratified random sampling. Obesity was defined as >+2SD NCHS (National Center for Health Surveys) reference. Data were collected by questionnaire, interview with mothers and were analyzed with Chi-Square and Fisher tests and multiple regression logistic models.

Results: In this study, 6.4% of children were obese. Prevalence of obesity was not significantly different between boys and girls (5.4% and 7.4% respectively). Breast feeding duration<18 months (P<0.005) and formula or cow’s milk plus breast feeding up to 6 months old (P<0.01) was significantly correlated with children’s obesity. Breast feeding duration more than 18 months reduced the obesity risk factor with 64%.

Conclusion: This study demonestrated that exclusively breast feeding in the first 6 months of life and breast feeding duration more than 18 months reduce the child obesity.