Two experiments were performed on growing pigs to determine the effects of potato protein and potato fibre on growth performance, apparent ileal and total tract digestibility, digesta transit time, blood biochemical parameters and small intestinal morphology. Apparent ileal digestibility (AID) of potato protein concentrate and most essential amino acids was significantly lower than that of casein. The substitution of potato fibre for cellulose did not affect significantly AID. Potato fibre tended to reduce the utilization of protein ingested. Passage rate of digesta was affected mostly by the type of fibre. Dietary protein and fibre did not influence the relative weight of stomach and jejunum whereas their effects on other segments were variable. Morphological parameters were affected either by protein and by fibre but course and magnitude of these effects were inconsistent and differed among the segments. In most cases interactive effects of both factors were found. Potato fibre did not reveal beneficial health effects on lipid metabolism.