The enterotoxemic from of calf colibacteriosis was observed on a total of 18 occasions in newborn animals. Clinically, the disease was manifested with diarrhea, depression of the eyes, fast dehydration, the calves tending to go down and lie for a prolonged periods, with high death rates. Some of the diseased calves showed nervous symptoms. Escherichia coli 0126 was isolated from the intestinal content and the mesenterial lymph of the affected calves. It proved virulent for albino mice. Morphologically, there were strongly expressed circulatory disturbances--hyperemia, perivascular edemas, hemorrhages (Fig. 1 and 2) thrombi (Fig. 3 and 5), with a vacuolar and parenchymal dystrophia of the liver, kidneys, and heart.