Purpose of the study was to determine biological effects of moderate water deficit on plasmalemma lipid composition in roots of two Z. mays varieties: drought-resistant “Dostatok” and non-resistant “Pereyaslavska” and also evaluate whether these changes could affect H+-ATPase activities and adaptation of plants to water deficit, respectively. Material and methods: plants grew in containers with sand substrate for 21-22 days of 80% moisture from plants (control) and 30% (experiment). The microsomal fractions enriched by plasmalemma were obtained from maize roots by two-phase aqueous polymer technique. Lipids were extracted from plasmalemma and their composition was analyzed by reversed-phase high performance liquid chromatography using Agilent 1100 HPLC-system. H+-ATPase hydrolytic activity was determined by the number of released inorganic phosphorus in nmol PO4 -3/mg protein / min. Water deficit causes increase of estimated sterol proportion in fractions of plasmalemma: in 32.6% of total lipids for “Dostatok” and in 27.5% of total lipids for “Pereyaslavska” variety. In our experiments, water deficit led to decrease of total amount of glycolipids in both varieties. This phenomenon occurred due to inhibition of cell signaling function. The major phospholipids were: phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylinositol (PI) and phosphatidylglycerol (PG). Following water deficit, we observed a reduction of these phospholipids. Dehydration caused a sharp decrease of major phospholipids, especially PC and PE. In general, “Dostatok” appeared to be more adaptive to water deficit. Modulation of phospholipid environment of the plasma membrane regulates activity of H+-ATPase. Activation of H+-ATPase depends on degree of un\saturation of fatty acyl chains and their length. Data obtained show that hydrolytic activity of H+-ATPase in plasma membrane of maize roots under conditions of adequate water supply was lower than under conditions of water deficit, in particular, in 2 times for variety “Dostatok” (225.67 52.8 nmol PO4 -3/mg protein / min / / 59.59 449.0±59.59 nmol PO4 -3/mg protein / min) and in 1.3 times for variety “Pereyaslavska” (117.93 ±27.05 / / 156.88 ±64.65 nmol PO4 -3/mg protein / min.).