The objective of this work was to compare the effect of selected feed mixtures on the duodenal morphology. One-hundred-four rats of the Wistar strain were divided to thirteen groups per eight rats. The experiment started in 35-day-old rats after birth and lasted for 32 days. The groups (A-M) were fed by commercial diet, 85 % wheat and 15 % oat diet, 85 % wheat and 15 % triticale, 85 % wheat and 15 % barley, 85 % wheat and 15 % amaranth, 85 % wheat and 15 % lantern, 85 % wheat and 15 % buckwheat, 100 % wheat, 100 % white lupine, 100 % flock peas – variety Garden, 100 % native peas – variety Garden, 100 % native peas – variety Zekon or 100 % extruded peas – variety Zekon diet, respectively. Samples from the duodenum were taken. The height of the villi and the depth of the crypts were measured. The tallest villi were measured in group F (474.33±114.36 µm) and the shortest villi were observed in group B (294.08±88.52 µm). The deepest crypts were measured in group K (166.41±35.69 µm) and the shallowest crypts were observed in group E (77.85±17.61 µm). The work documents that gluten-free and classical cereals combination can be a better choice for people who want to limit the gluten content of the diet.