The diploma thesis deals with the study of the evaluation of soil aggregates proportion and the coefficient of structure in the most widespread soil type in Slovakia. For this purpose, soil sampling was performed in the locality of NPR Havešová located in NP Poloniny. Samples were taken from the upper soil horizons from a depth of 0–10 cm, then processed in the laboratory and the individual fractions of soil aggregates were separated using an automatic sieving device. After separation, each fraction was weighed and converted to a percentage. The percentage was used mainly to compare the samples with each other, while the coefficient of soil structure was calculated based on the weights of the individual fractions. Based on the calculated values of the structural coefficient, it can be stated that the soils around NPR Havešová are mostly structurally favorable. Deterioration of structural properties can be expected on areas with a higher proportion of clay fraction in fine soils, due to a higher proportion of structurally unfavorable coarse aggregates.