In 80 calves presented with clinical signs of umbilical disease, the umbilicus was examined by palpation and by ultrasonography using a 5 Mhz or a 7.5 Mhz sector scanner. Diagnosis was confirmed during surgery or at post mortem examination. The various diseases of the intraabdominal umbilical structures found in these calves and the therapeutic procedures performed are described in detail by use of schematic representations, photographs of anatomical preparations, and ultrasonograms. In 29 calves with an enlarged extraabdominal umbilicus, ultrasonographic examination provided additional information to determine the choice of therapy, and it was particularly helpful in calves with irreducible hernias and with umbilical abscesses. In 51 calves with diseases of the intraabdominal umbilical structures, an exact description of the extent of the disease and of the involvement of other structures, as the liver and the urinary bladder, was made possible by ultrasonography. In calves with omphalitis, early recognition of the involvement of intraabdominal umbilical structures could be determined. Umbilical ultrasonography can be performed easily and is a very reliable and informative aid not only in the diagnosis of umbilical disease but also in determining the choice of therapy. Additionally, the owner can be informed in advance about the expense and the prognosis of the planned therapy.