Objective : to undertaken in a group of type 1 diabetic patients who were followed for 4 years to shed further light on the natural progression of cardiac autonomic neuropathy. Patients and methods : The study consisted of 57 patients who were originally studied using a battery of five cardiovascular autonomic tests . Two years later , 46 patients were reevaluated, again 2 years later, 55 patients from the original study were reevaluated for the 3 time using the same protocol. The control group comprised 30 age and sex matched healthy volunters. Results: The prevalence of established cardiac autonomic neuropathy (CAN) at the beginning is 14%. Q-Tc intervals were found to be significantly higher in patients with abnormal cardiovascular reflex (CVRs) in 2 examination. Eighteen patients of the original studied group showed deterioration of their CVRs test between 1 and 3 examination , there is deterioration of their glycemic control guided by glycosylated hemoglobin and albumin / creatinine ratio. On the other hand, 12 patients of the original studied group showed regression of their CVRs test. Only their insulin dose showed significant decrease. Conclusion: The prevalence of CAN in diabetic patients is high. Our data suggest that valsalva – stimulated heart rate response is highly susceptible to the presence of autonomic dysfunction over time. Proper glycemic control is mandatory to prevent development of diabetic complications or ameliorate the preexisting complication [Journal of American Science. 2010;6(10):252-259]. (ISSN: 1545-1003).