Aroma in samples of two varieties of Agaricus bisporus, i.e. KORONA 7 and EUROMYCEL 12, was analysed in terms of contents of eight carbon atom compounds (1-octen-3-ol, 3-octanone, 3-octanol, 2-octen-1-ol). Carpophores were harvested in 4 flushes according to their cap sizes. Quantitatively the dominant compound in all samples was 1-octen-3-ol, found in the highest concentrations in the 1^st flush of yielding. The analysis of variance for factorial experiments, performed for both cultivars in one cultivation cycle – 2001/2002 and for one variety – KORONA 7 in two cycles, showed the effect of mushroom variety, flush of yielding and carpophores size on contents of dry matter and aromatic volatiles. Carpophores of a smaller cap diameter were characterised by a higher dry matter content and usually also higher contents of aromatic volatiles. In contrast, the effect of flush of yielding was different: the highest content of dry matter was recorded in the 4^th flush, while that of aromatic compounds in the 1^st flush.