The aim of our study was to determine whether there is any correlation between cardiac autonomic function and insulin resistance in patients with hypertension with and without type 2 diabetes. The Ewing reflex test battery was performed in 81 hypertensiv subjects, 38 with and 43 without type 2 diabetes, and in a control group. HOMA-IR was significantly higher in hypertensiv subjects with diabetes, and it was significantly higher in both groups, than in the control group. Autonomic neuropathy was more often present in the insulin resistant group. The insulin resistant group had also higher heart rate, longer QTc. Insulin resistance could be a basic risk factor for the development of autonomic neuropathy and abnormal autonomic cardiovascular function.