Sedimentological investigations and thermal analyses were carried out in a steep slope vineyard in 2007 (Nagy-Eged hill – located in the north-eastern part of Hungary). This area is proned extremely eroded due to its significant steepness and vine-growing cultivation. Soil thickness is approximately 50 cm near the top while at the bottom the thickness of horizon A alone reaches up to 150 cm. According to the results the ratio of fractions smaller than 0.02 mm and those larger than 2 mm between the top and the bottom is reverse. In the lower slope section the ratio of particles smaller than 0.02 mm is three times that in the upper slope section. Similarly the ratio of particles larger than 2 mm in the lower slope section is five times that in the upper slope section. The quantity of clay minerals measured by thermal analysis is larger than that measured by elutriation indicating that a part of them exceeds the diameter of 2μm. Our results revealed the effects of soil erosion on the mineral composition of the soil. The amount of clay minerals (e.g. montmorillonite) is about the double in the lower section, than in the upper of the slope. Clay minerals caused negative water budget in the upper levels resulting in the occurrence of anthropogenic water deficit as the consequence of soil erosion. Therefore vegetative growth of plants in the lower areas is better than that of those in the upper areas.