The study was carried out in 2007-2009 at the growth chamber of the Institute of Soil Science and Plant Cultivation – National Research Institute in Puławy, in Mitscherlich pots containing a mixture of 5 kg of hortisol and 2 kg of sand. 1^st order factor was soil moisture: 30 and 60% of field water capacity (FWC), and 2^nd order factor – a way of sowing: pure sowing of lupine – 5 plants, mixed sowing – 3 lupine plants and 6 barley plants and pure sowing of barley – 10 plants∙pot^-1. Blue lupine of the cultivar Sonet and barley of the cultivar Johan were sown in the experiment. The aim of this study was to estimate the response of a determinate cultivar of blue lupine grown in pure sowing and in mixture with barley to drought stress occurring in the flowering period. A lower sensitivity to drought of the lupine-barley mixture than of lupine cultivated in pure sowing was observed. Under conditions of the optimal soil moisture (60% FWC) sowings of lupine with barley gave the highest yield, whereas under conditions of water deficiency in soil barley grown in pure sowing gave the highest yield. For the reason of a larger yielding stability, under conditions of expected water deficiency in soil it is better to cultivate blue lupine with barley than in pure sowing. Planing such sowings, it should be taken into account that in spite of high yields they provide less lupine seeds than pure sowings of this species.

61-74