Autonomic diabetic neuropathy of cardiovascular system is one of the late diabetic complications. The aim of the study was to compare heart rate time domain analysis in 23 healthy controls and in diabetic patients without (N0; n = 34) and with complications (N1, n = 55) such as retinopathy, peripheral neuropathy as well as autonomic neuropathy. The study was performed in a group of 89 patients with diabetes mellitus type 1. Classical tests of Ewing battery (upright test, Valsalva test, deep breathing test) were performed using the ProSciCard machine as well as parameters of time domain analysis were observed during prolonged to 15 minutes standing in upright body position. Comparing group N1 to group N0 significantly higher heart rate, lower standard deviation of RR interval as well as lower value of rMSSD both at rest and during prolonged stay in upright position were demonstrated.