The texture of extrudates under investigation was investigated using a TA-XT2i texture analyzer. The following tests were performed: texture profile analysis, breaking test, and cutting test. The texture parameters of the extrudates: hardness, fragility, resilience, cohesiveness, and springiness were determined, and the expansion of the extrudates under investigation was studied. While increasing the content of oat grinding grains, wheat flour, and oat flour in extrudates (up to 50%), it was necessary to increase forces required to cut and break the extrudate samples. The final product was harder and not very fragile. Samples with the addition of about 60% of com grits showed an average hardness. The higher amount of oat grinding grains, oat bran, and oat flour added to the extrudates during the extrusion process resulted in the decreasing value of the expansion coefficient of the extrudates produced (the coefficient changed from 15.2 in an ‘M 2’ sample containing 20% of oat grinding grains to 1.2 in a ‘V 3’ sample with 70% of oat grinding grains). The type of an extruder applied and the temperature profile essentially impacted on textural properties of the extrudates and on their expansion. It was stated that if the amount of raw materials of oat added was higher than 40%, the extrudates obtained from a ‘VALEUREX’ extruder had better textural features than the extrudates produced by a ‘Metalchem’ extruder.