Eighty-eight type I diabetics were subjected to neurological and myographic examination and tests were performed assessing the condition of the vegetative nervous system. Forty-four patients (50% of the group) suffered from diabetic nephropathy with different expression in the stage of chronic renal failure. The authors revealed significant positive correlation between the results of tests of vegetative neuropathy and all evaluated parameters of the neurological and electromyographic finding. In patients with a S-creatinine level above 125 mumol/l in both tests of vegetative neuropathy and in all examined parameters of peripheral nerves highly significantly lower values were recorded than in diabetic patients with normal renal function. In diabetics without renal insufficiency, however, the correlations between the findings on the autonomous and peripheral nervous system were also statistically significant.