For some time Norwich terriers have been known to suffer from respiratory problems. In order to assign this weakness to a pathophysiology, 23 terriers were examined clinically, with laryngoscope and with rhinomanometry. In addition their skulls were dimensioned on radiographs. Widened nostrils, overlong soft palates and the everted laryngeal pouches were consistent with brachycephalic syndrome. Resistance values in the nasal passage corresponded to the appearance in brachycephalic dogs. Skull measurements gave inconsistent results, because length to width ratios and craniofacial angles denoted mesaticephaly, whereas the facial to cranial length ratios (S-index = 0.65) lay in the brachycephalic sector. It can be concluded, that the Norwich terrier breed is in transition towards brachycephaly with some individual dogs already suffering from the brachycephalic syndrome. Breeders are requested to introduce necessary counter measures.