The fatty acid composition of some lipid fractions in female catkins of Betula pendula Roth was studied for the first time by the phases of their spring and summer development. We found that pistillate flowers prior to pollination contained nearly twice more neutral lipids than phospho.and glycolipids, and accumulation of saturated fatty acids was observed in all other fractions. The activation of metabolic processes in female catkins following pollination was accompanied by a rise in phospho. and glycolipids simultaneously with an increase in the proportion of unsaturated fatty acids, mainly owing to mono. and/or diene acids.