Studies were carried out in a long-term experiment at different fertilisation. The aim was to assess the effects of renovation in terms of yielding, botanical composition and the content of proteins and soluble carbohydrates in meadow sward at different fertilisation. Five experimental plots were fertilised with mineral fertilisers at a rate of 60, 120, 180, 180bis and 240 kg N·ha-1, respectively and two plots were fertilised with both mineral fertilisers and cattle liquid manure at a combined rate of 180 and 240 kg N·ha-1 (plots G1 and G2, respectively). Phosphorus and potassium were applied in doses proportional to N fertilisation. In plot N-180bis fertilisation with phosphorus was abandoned since 1997. Distinctly worsening botanical composition of the sward with a great share of low grasses (>60% in most plots), a lack of legume plants and a substantial weeding (from 14 to 28%) by stubborn weeds, particularly on plots of higher fertilisation, indicated the need for renovation. The renovation by direct undersowing with a special turf-processing machine was made in spring 2012. In subsequent years a distinct domination of tall grasses and decreased weeding was observed. The yield significantly increased in 2013 compared with that in 2011 was noted on plots N-180, N-240 and G2. In 2014 the yield was larger on all plots regardless of fertiliser doses. Total protein content in sward was optimum in 2011 and markedly decreased after undersowing. Decreased protein content resulted from the elimination of dandelion and other protein-rich dicotyledons from the sward and from the increased share of grasses (mainly oat-grass) in 2014. Nevertheless, total protein yield was higher in 2013 and 2014 than in 2011.