The authors investigated in 194 type I diabetics the incidence and severity of diabetic polyneuropathy in relation to other organ and vascular complications, incl. autonomous neuropathy. It was revealed that the increasing severity of polyneuropathy was significantly v séru (Cr equal to or less than 130-200 mumol/l); 4--Cr greater than 200 mumol/l; associated with severe stages of nephropathy and proliferative retinopathy with amaurosis. The concurrent presence of hypertension and polyneuropathy was surprising and striking--even in patients with the mildest grade 1 polyneuropathy hypertension was present in 10% and the incidence increased significantly with the increasing severity of polyneuropathy. Ischaemic heart disease and ischaemia of the lower extremities was significantly more frequent only in patients with grade 5 polyneuropathy. In patients with grade 4 and 5 neuropathy there was a 100% incidence of autonomous neuropathy in the cardiovascular sphere. The authors did not reveal significant differences between men and women as regards the relationship between the incidence of polyneuropathy and organ and vascular complications.