In the Agricultural Experiment Station, Grabów, Institute of Soil Science and Plant Cultivation-National Research Institute (voi. Mazovia) farm converted to organic farming in 2006-2009 a field experiment was carried out strict, two-factor for protein yield in the cultivation of four legume-grass mixtures with 60% and 40% for the seeds legumes and grasses in a mixture of seeds (first factor) in terms of fertilization in two doses of composted manure (sec ond factor). It was found that in the year of the periodic shortage of moisture in soil organic farm growing lucerne mixtures with grasses was more favorable because of higher dry matter yield, participation of the legume plants in mixed sward, the protein content by gźkg-1D.M. and protein yield than red clover mixed with grasses.