An association between obesity and cardiac mass  has been recognized for almost two decades, whereas the precise nature of the association remains elusive Theoretical consideration have long suggested that it may be mediated at least in part by insulin resistance (Mc, Nutly  ,2003).Several studies have found an association between insulin resistance and left ventricular hypertrophy.(Lacobellis et al,2003) In human, production of leptin( an adipocyte – derived peptide), has been linked to obesity, insulin and insulin sensitivity (Leyva et al, 1998) .It was considered that alteration in plasma concentration could constitute an additional component of metabolic syndrome of cardio-vascular risk(Leyva et al, 1998).   Aim of the work: The aim of this work was to evaluate the relationship between obesity, insulin resistance, leptin and left ventricular mass and function in young obese females with insulin resistance.   Subjects and methods: Sixty five premenopausal females aged 25-45 years with no history of diabetes or hypertension was participated in this study. Twenty were non obese and forty five were obese .Fasting serum glucose, insulin and leptin were assessed and homeostatic model assessment HOMA-IR score was calculated. According to HOMA-IR obese premenopausal females were divided into 2 subgroups: - Subgroups 1: (Insulin sensitive group or IS group) included 20 obese females with HOMA-IR Subgroup 2: (insulin resistance group or IR group) included 25 obese females with HOMA-IR≥3.8.Echocardiography was done for all females participated in the study to evaluate L.V mass and function.   Results: Waist circumference (WC), serum insulin, serum leptin and HOMA-IR were significantly higher in obese group compared to non obese group (p<0.05, <0.05, 2.7 (LVM/h^2.7 )were significantly higher in obese group compared to non obese group (p<0.05) and between IR and IS subgroups (p2.7 and serum insulin (p<0.05)and serum leptin (p<0.05) in IS subgroup while the correlation was highly significant between both and fasting leptin (p<0.001)  in IR subgroup   Conclusion: Obesity is a clinical syndrome associated with hyperinsulinemia, hyperleptinemia and insulin resistance Abnormalities of LV diastolic function and mass occur frequently in obese patients. Hyperleptinemia can be an early sign for left ventricular dysfunction in obese females.