Tehran University of Medical Sciences Iranian Journal of Public Health 2251-6085 55 1 2026 02 08 162 172 Mojtaba Norouzi Department of Epidemiology and Biostatistics, School of Health, Shahrekord University of Medical Sciences, Shahrekord, Iran Naser Nasiri Department of Public Health, School of Health, Jiroft University of Medical Sciences, Jiroft, Iran Sasan Amiri Faculty Member, Department of Nursing, Faculty of Nursing and Midwifery, Hormozgan University of Medical Science, Bandar Abbas, Iran Habibeh Nasab Environmental Science and Technology Research Center, Department of Environmental Health Engineering, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran Nahid Bagheri Modeling in Health Research Center, Institute for Futures Studies in Health, Kerman University of Medical Sciences, Kerman, Iran Mostafa Eghbalian Department of Epidemiology and Biostatistics, Faculty of Public Health, Social Development and Health Promotion Research Center, Gonabad University of Medical Sciences, Gonabad, Iran Parvaneh Nazari Clinical Research Development Unit, Shafa Hospital, Kerman University of Medical Sciences, Kerman, Iran Reza Faryabi Department of Public Health, School of Health, Jiroft University of Medical Sciences, Jiroft, Iran 2025 04 27 2025 12 08 Background: We aimed to investigate the factors that influence the prevalence of obesity and overweight in children in Jiroft, Kerman Province, Iran using tree regression analysis.  Methods: A cross-sectional study was conducted in 2024.  Children aged 2-6 years were selected from the kindergartens of Jiroft City by a stratified random sampling method. Parents' demographic information, the mother's health information during pregnancy, nutrition, and the child's lifestyle were obtained through a questionnaire. Children's BMI Z-score was measured. A decision tree model was built using the "rpart" package in R software (version 4.5.1). Results: Out of 1032 children aged 2-6 years, 51.0% (n=522) were girls. The factors affecting the BMI of children include having a father weighing more than 89 kg, a high-income family, and a birth weight of less than 3.1 kg. According to the regression model, mother's job (P-value=0.045), father's weight (P-value=0.002), and birth weight (P-value=0.013) were positively associated with higher child's BMI status. In contrast, daily vegetable intake (P-value=0.044) was negatively associated with current BMI. Conclusion: Fathers' weight, family income, and vegetable intake are key factors influencing early childhood BMI in Jiroft. Targeted interventions should prioritize engaging fathers in weight management programs before and during their child’s formative years. Obesity prevention efforts must also address lifestyle behaviors in affluent households through tailored nutritional counseling. Regular vegetable intake appears to have a protective effect, contributing to lower BMI in children.  https://ijph.tums.ac.ir/index.php/ijph/article/view/38910 https://ijph.tums.ac.ir/index.php/ijph/article/download/38910/8756