Background: Echocardiography is the leading and feasible cardiac imaging in patients with cardiac disease. An early evaluation of patients with complex coronary lesions plays an important role in the prognosis and selection of treatment strategy. Objectives: To compare and determine the value of 3D speckle tracking echocardiography (3D SE) at rest in diagnosis of coronary artery disease (CAD) in stable angina pectoris patients using SYNTAX score as a reference. Patients and methods: A total of 90 patients with stable angina underwent invasive coronary angiography (CAG) enrolled into study from Islamic Cardiac Center at Al-Azhar University during the period from April 2017 to December 2019 and classified to case and control groups based on CAG results. Subjects underwent CAG and 3D-STE examination and SYNTAX score calculation, and then the patients were sub grouped according to SYNTAX score. Results: There was a significant difference in strain measurement (Global longitudinal, circumferential and radial strain) between SYNTAX score sub-groups. The absolute value of different strain measurements decreased from low SYNTAX score to intermediate or high SYNTAX scores. For GLS was -14.8±1.9%,-11.08±1.7 and -7.4 ±1.2, respectively, and for GAS was -39.5±1.08,-25.95±7.09 and -14.6±1.86, respectively, and for GCS was -24.47±3.89,-14.96±2.41 and -8.73± 2.53, respectively, using ROC curve analysis the cut off value of GLS that differentiate between high SYNTAX score (≥33) and non-high score (≤32) was -7.7 and -17.1 for GAS and -12.5 for GCS. The cut off value of GLS that differentiate between low SYNTAX score (≤22) and non-low score (≥23) was-12.5. Conclusion: Three-dimensional -STE is a noninvasive, reproducible, and efficient tool that has a potential clinical practice to evaluate the coronary lesion in chronic coronary syndrome patients. The absolute values of stain parameters were significantly associated with the complexity of coronary artery lesions.