The aim of the experiment done in 2000–2002 on sandy soil of a good-rye-complex was to find optimal proportions of Trifolium repens and Festulolium braunii seeding with various doses of nitrogen fertilization. The field experiment of two factors was arranged by the split-plot method in four replicates. The area of one plot was 12 m2, 1st factor: share of Trifolium repens cv. sown with Festulolium (Felopa) (0, 30 and 50%), 2nd factor: level of nitrogen fertilization (0, 80, 140 and 200 kg N ha-1). The floristic composition of sward and the content of protein were analysed, and the yields of green and dry matter were recorded. Botanical analysis showed that the share of Trifolium repens in both mixtures reached 46–29% in the first year and 39–19% in second year of full utilization. A sagnificant interaction between mixtures and doses of nitrogen fertilization was found. The combination where Trifolium repens was sown in 30%, Festulolium in 70%, and dose of nitrogen – 140 kg ha-1, was the most advisable.