The present study includes the results of comparative investigations of aggregate composition and water stability of structural aggregates in humus horizons of non-calcareous rendzina under native forest and pasture vegetations and the same rendzina utilized long-term as arable field. The results show that aggregate composition and water stability of structural aggregates in the cultivated non-calcareous rendzina are significantly impaired due to a long-term anthropogenization. In the cultivated rendzinas the content of agronomically most valuable aggregates (0.25-10 mm) significantly decreased, while the percentage of cloddy aggregates (>10 mm) was increased about 1.5 to 3.5 times in comparison with the rendzina under pasture and forest vegetations. The structure coefficient of cultivated soils was lower (2.61) than in forest (4.63) and pasture (10.47) rendzinas. The cultivated non-calcareous rendzina had lower (59.12%) aggregate water stability than rendzina under pasture (82.66%) and forest (91.92%). Mean weight diameters of water stable agregates was higher in forest (1.44 mm) and pasture (1.20 mm) than in cultivated (0.65 mm) rendzina.