Background: Insulin resistance (IR) is the primary metabolic disorder associated with obesity. Obesity is a growing worldwide health problem affecting both adults and children. Objectives: To determine the association between leptin and IR, and to identify the ratio of fasting glucose/leptin (G/L) and insulin/leptin (I/L) as a new simple method for the detection of IR in obese children.Methods: This study was done in the National DiabeticCenter/ AL-Mustansiriya University during the period fromMay 2013 until the end of October 2013. Fasting bloodglucose (FBG), serum insulin, leptin, and lipid profile weremeasured in 52 obese children (24 children with IR and 28without IR); their age range was (5-15) years, they werecompared with 38 healthy children as a control group.Results: Means of FBG, insulin, leptin, total cholesterol(TC), triacylglycerol (TAG), low density lipoproteincholesterol (LDL-C), and non high density lipoproteincholesterol (non HDL-C) were significantly increased inobese children with IR as compared in children without IR,(P<0.05), while there was a significant decrease in serumlevel of high density lipoprotein cholesterol (HDL-C) inobese children with IR when compared with obese childrenwithout IR, (P=0.001). There was a decrease in the ratio ofG/L and an increase in the ratio of I/L in obese children withIR, but it was not significant. A significant positivecorrelation was found between serum leptin verse bodymass index (BMI), FBG, insulin, homeostasis modelassessment for insulin resistance (HOMA-IR), I/L ratio, TC,TAG, LDL-C, and non HDL-C, while a significant negativecorrelation was found between serum leptin and HDL-C inobese children with IR.Conclusions: The present results showed that serum leptinis correlated with BMI, FBG, insulin, HOMA-IR, I/L ratio, TC,TAG, LDL-C, and non HDL-C in obese children with IR. TheG/L ratio can be used in addition to me /L ratio, and HOMAto accurately assess IR in obese children