The digestibility of energy and nutrients was determined in piglets weaned at 10 kg and fed a standard diet B, with a fibre (F) content of 37.9 g/kg, or diets with the F content increased to 53.5, 60.6 and 76.4 g/kg (diets GM10, GM15 and GM20, respectively). The diets were fed until 25 kg BW and then were replaced by diet B fed to all pigs for 14 days. During the last 5 days the digestibility of diet B was measured in pigs previously fed on diets with increased F contents. In diets with a higher F content, the digestibility of energy and nutrients, except F, was lower, whereas the digestibility of F was higher than in diet B. Consequently, the energy value of these diets was lower by 0.9-1.1 MJ ME. The energy and nutrient digestibilities of diet B fed after diets with a higher F content were not affected by the preceding diet except NDF and F digestibilities, which were digested better. The energy value of diet B fed to pigs pre-fed on high-fibre diets was from 0.15 to 0.21 MJ ME greater as compared with that of diet B fed continuously.