The purpose of the work was to determine the effect of the fi bre content in the mixture on morphometric traits of intestinal epithelium of fatteners. In one-phase fattening, 14 crossbred pigs were classifi ed into two groups and ad libitum fed the mixtures, differing in the composition and nutritional value, including the level of crude fi bre (control group – C – 3.4%; experimental group – E – 12%) but with the maintained energy-protein ratio (1 : 13). At the age of 180 days, the fattening was completed; the weight of the pigs from C group was equal to ca. 100 kg and that one of the pigs from group E was by ca. 26 kg lower. The rate of growth of pigs from group E as compared to the animals from group C was slower (P ≤ 0.01). After slaughter, morphometric evaluation of the scrapes from the following three segments of the small intestine was carried out: duodenum, jejunum and ileum. There was found a lower mitosis index (the number of divisions per one crypt) of the intestinal epithelium cells of the pigs from group E as compared to group C (duodenum, P ≤ 0.01). The height of the epithelial cells in crypts and depth of crypts in three examined segments of small intestine (D, J, I) was higher in group E vs. group C (P ≤ 0.05; P ≤ 0.01), whereas the villus height was lower in group E vs. group C. The fi bre level in the mixture affected the direction and level of changes in the examined indicators, characterizing the morphometric traits of intestinal epithelium.