Obesity is characterized by abnormal or excessive fat accumulation that is the result of a chronic imbalance between energy intake and energy expenditure. The aim of this study is to estimate the concentrations of leptin, T3 hormone, T4 hormone, TSH, MDA, GSH, Zn, Mg, lipid profile (cholesterol, HDL-c, LDL-c, VLDL-c, and triglycerides), atherogenic index, glucose and BMI in all the study samples, study the correlation between leptin and other biochemical parameters including: T3hormone, T4hormone, TSH, MDA, GSH, Zn, Mg, lipid profile, atherogenic index and glucose among obese individuals and the control group. This study was conducted from the beginning of January 2015 until the end of October 2015. Blood samples have been collected from a total 176 persons. All individuals were randomly taken from private laboratories in Kirkuk Governorate, and their ages were between 20-55years. Blood samples were divided into three groups according to BMI. Group one - control group (Normal weight): 66 individual (32males, 34females), BMI (18.5 - 24.9 kg/m2). Group two- overweight group: 50 individual (16males, 34females), BMI (25.0 - 29.9 kg/m2).