The affectivity of extrusion process of pea seeds on nutrients digestibility or growth performance of pigs was analysed. The first study was conducted on 30 male pigs allocated to three dietary treatments for 28 days. The control animals were offered a basal diet whereas the experimental groups received basal diets mixed with raw or extruded pea seeds in the proportion of 75:25 (w/w). The apparent ileal and total tract digestibilities were determined using the difference method with titanium dioxide. The second semi-practical experiment was conducted on 60 pigs (29 ± 0.3 kg) and lasted 75 days. The growth performance of the pigs receiving control diet with soyabean meal (SBM) or diets where SBM was replaced with raw or extruded pea seeds mixed with rapeseed meal (RSM) was analysed. The extrusion of pea seeds significantly reduced the content of resistant starch, phytate-P, crude fibre and neutral detergent fibre levels, and trypsin inhibitor activity. Extrusion only enhanced (P < 0.05) the apparent total tract digestibility of crude protein, and improved the apparent ileal digestibility of Asp, Glu and Cys (P < 0.05). The inclusion of pea seeds with RSM into the diet of growing pigs reduced their daily gain and feed conversion ratio, but not during finishing phase and during the whole time of experiment. The final body weight of pigs receiving pea seeds and RSM was lower in comparison to the control group. In conclusion, extrusion significantly influenced the chemical composition of pea seeds but it did not improve the production results of the animals.