Background: Obesity and diabetes mellitus are the common health problems,and obesity is common cause of the insulin resistance. Aim of studv: Aim of the study is to find any correlation between obesity (insulin resistance) and type I diabetes in children. Patients and methods: This study included (40) children with type I diabetes, in addition to (40) children as control.The age of all studied groups ranged from (8-18) years.This study was attemted from Ibn AlBalady Hospital during from 20 August to 9 Novembar,2008. The subjects wrer divided into (4) groups according to their BMI:- * Obese children,diabetes,n=2O,BMI>30. * Non obese children, diabetes, n=20,BMI<25. Obese children, non diabetes, n=20,BMI>30. * Non obese children,non diabetes, n=20,BMI<25. Venous blood samples were collected , 2ml parts in EDTA tube and used for HbAlc measurement by Alc variant reader and a second part in plain tube for measurement of glucose and insulin .Insulin resistance was determined by mathematic relation (HOMA). The results: The results revealed marked increased in glucose, insulin , HbAlc and insulin resistance in obese diabetic type I patients comparing to control group they were obese and non obese found to bewithin normal values for glucose, insulin , FIbAlc , and insulin resistance . Conclusion: BMI is a factor for insulin resistance. * lnsulin resistance is an evident observation, had a significant correlation with diabetic children type I . * Insulin resistance reflected the degree of metabolic control so as HbAlc reflect the degree of metabolic control'