Background: Left ventricular heart failure in sitting of preserved left ventricular ejection fraction constitutes up to 50% of heart failure. It increases with age and is correlated with the presence of systemic hypertension and left ventricular hypertrophy. It has significant morbidity, approaching that of systolic heart failure. Heart failure preserved ejection fraction (HFpEF) is a clinical syndrome resulting from increased resistance in the filling of the left ventricle (LV) leading to symptoms of congestion although the exact cause continues to be unknown and the identification of markers that predict HFpEF risk have not been proven. Aim of the Work: Assessment of left ventricular diastolic function in patients with heart failure and preserved ejection fraction. Patients and Methods: This study included 90 patients with ages ranging from 30 to 70 years old referred to Al Hussein University Hospital, Bab Al Shearia University Hospital, Cardiology Outpatient Clinic suffering from low functional capacity, exertional dyspnea and even exertional chest discomfort. Over a period from November 2015 to May 2018. The study population was divided into two groups according to incidence of positive stress ECG. Group A (patient group): Patients with positive stress ECG. Group B (control group): Patients with negative stress ECG. Results: This study included (90) patients with their ages ranging from 30 to 70 years referred to (Al Hussein University Hospital), (Bab Al Shearia– University Hospital) cardiology outpatient clinic from November 2015 to September 2017, with low functional capacity, exertional dyspnea and even exertional chest discomfort and are evaluated to rule out coronary artery disease (CAD). Those patients were evaluated by stress ECG and Transthoracic Echodoppler and Tissue Doppler imaging. The study population was divided into two groups according incidence of positive stress ECG into: Groups according incidence of positive stress ECG. Group I patients group: Included 60 patients presented by chest pain with dyspnea NYHA class 1 (12 patients), class II (37 patients), or class III (11 patients) with mean age 54.05±7.9 years, this group included 19 females (31.7%) and 41 males (68.3%), Group II control group: Included 30 patients with mean age 52.7±5.11 years. Female number was 13(43%) and males were 17(60%). Conclusion: The assessment of diastolic function is now essential on routine testing for HF. The noninvasive nature of echocardiography has allowed an increase in diagnosis and awareness of diastolic dysfunction.