The studies on iron and aluminium forms and soil forming processes quantification in Chernozems were conducted in two localities in Western Slovakia. Two soil pits were done in a complex of arable Haplic Chernozems in Krakovany and two soil pits representing arable and forest Cambic Chernozems were done in Báb. The soils were sampled every 10 cm and analysed using standard methods. Based on analytical results, profile development indices (PDI) were calculated for each profile. Chernozems in Krakovany were characterised by 90 cm (Krakovany 1) and 80 cm (Krakovany 2) thick solums and pH increasing with depth from neutral to alkaline. The content of total organic carbon (TOC) was up to 13.70 g kg-1 in both profiles. Cambic Chernozems in Báb were characterised by a lower thickness of solum – 40 cm in arable soil (Báb 1) and 70 cm in forest soil (Báb 2). Reaction of arable soil ranged from slightly acid to alkaline, and in the case of forest soil – from strongly acid to alkaline. Arable soil contained 14.2-14.5 g kg-1, and forest soils 12.9-50.7 g kg-1 of TOC in A horizons. The content of Fet in the studied soils ranged from 21.78 to 32.48 g kg-1, free iron oxides (Fed) – from 5.74 to 11.53 g kg-1, and amorphous iron oxides (Feo) – from 0.77 to 2.94 g kg-1. Fed/Fet ratios ranged from 0.26 to 0.39. Crystalline forms predominated over amorphous ones. The values of PDI were relatively low, namely 1.50 – in the profile Krakovany 1; 1.76 – in the profile Krakovany 2; 1.15 in the profile Báb 1 and 2.12 – in the profile Báb 2.