In 2009 maize and sorghum was studied in a weighable lysimeter experiment in order to determine the water use efficiency of these two plants as farmers often have the dilemma if maize can be substituted by sorghum even with benefit (eg better water use efficiency) under the soil-and climatic conditions of the Great Hungarian Plain. This question is arisen even with a greater emphasis under irrigated conditions, especially as the safety of plant production can be ensured only by irrigation in droughty periods. One maize and one sorghum hybrid in three replications were applied as indicator crops for the comparison. In 2010 three different sorghum hybrids were studied under irrigated and non-irrigated conditions. For both years water balances for different time frames were calculated involving the determination of each component of them. On the base of the different yieldand water balance parameters indexes characterising the water use efficiency of the crops were also calculated. It could be concluded that in a normal, dry year sorghum consumed 10 percent more water than maize under irrigated conditions. In the wet year somewhat lower evapotranspiration, but very much better water use efficiency characterized the 3 investigated sorghum hybrids.