Over the past fifteen years there has been a significant increase in the areas under sunflower in Bulgaria. The oilseed hybrids present a larger share in this respect. The increased areas under sunflower during that period was due to the: – changed situation of agriculture in Bulgaria; – construction and equipment of a number of oil mills; -relatively small investment in the cultivation of sunflower; – the massive influx of established global companies for production and distribution of sunflower seed into the Bulgarian market. This requires cultivation in some areas to be carried out on different soil types, some of which are not quite suitable for the purpose although sunflower has a high tolerance for growing on different soil types. The results of the structural components of the yield and, respectively, sunflower seed are a criterion for the genetic adaptation to them. The purpose of this paper is to identify structural components of the yield and seed yield of four oilsunflower hybrids – Albena, Mesta, Magura and Murgash, grown on alluvial-meadow soil.