Background: Improving recovery after exercise is vital for decreasing cardiac mortality by dominance of parasympathetic nervous system control in recovery time. Objective: To determine the influence of coronary artery disease on heart rate recovery after exercise in patients with diabetes mellitus. Patients and Methods: The ethical approval was obtained from the hospital ethical research committee, in cardiology department in Al-Hussein university hospital from March 2019 to November 2019 and each patient signed an informed consent. Fifty patients were included in this study divided in 4 groups, all with no evident history of ischemic heart disease. Detailed history, physical examination, resting ECG, trans thoracic echocardiography, and finally treadmill exercise stress test was done. In this study we assessed heart rate recovery in 1^st, 2^nd& 3^rd minute and also basal heart rate included. Results: Significant delay in heart rate recovery time was detected in diabetic patients with positive stress ECG test for myocardial included ischemia. Conclusion: Delayed recovery and reduced heart rate recovery after treadmill exercise stress test is an available and important index for detecting and revealing the extent of ischemic burden.