A field experiment was carried out on a sandy soil in 1992-1994. The effect of supplemental irrigation and mineral fertilization on the yield of three cultivars of spring wheat was evaluated. It was found that irrigation caused an increase of the yield of grain by 143%, while high mineral fertilization - by 64%. The yield of grain increased by 240% as the effect of both treatments. The ‘Hera’ cultivar has demonstrated the biggest response to both treatments applied and gave the highest yield (8,64 t/ha). Supplemental irrigation and high NPK rates, along with a better tillering, resulted in a larger assimilation area of the leaves and higher chlorophyll and carotenoids content. High rates of NPK limited weed infestation.