The study was undertaken to investigate the effect of RS4 resistant starch in high-fat diets on the apparent absorption of magnesium (Mg) and iron (Fe) in Wistar rats. The animals (4 groups of males, n=32) were fed 4 types of diets: a control diet with 15% addition of soybean oil (K₁) and a control diet with 15% addition of lard and cholesterol (K₂) as well as 2 respective experimental groups with 10% addition of RS4 resistant starch (K_1S and K_2S). After a 3-week adaptive period, the animals were transferred into metabolic cages. Feed intake was measured and samples of faeces were collected within the 3 subsequent days. Diets and faeces were determined for contents of Mg and Fe with the method of atomic absorption spectrometry. The absorption of Mg and Fe in rats was calculated based on a difference between their contents in ingested diets and excreted faeces. An increase was observed in the apparent absorption of magnesium and iron by ca. 8% and 17.5%, respectively, in the group of rats fed the high-fat diet (lard + cholesterol) and resistant starch (K_2S) as compared to the control group (K₂).