This work evaluates the possibility to substitute external soya bean, a high risk GMO alimentary source, with other legumes produced on farm, such as sweet lupin, protein pea and field bean, as alternative protein source in the formulation of diet in organic dairy cattle nutrition. In 2005/2007 periods both the field and feeding trials were carried out in an organic dairy farm in Tuscany. The performances of grain legumes crops were evaluated in terms of grain yield and quality of grains. The alimentary experiment was carried out on dairy cattle fed with two diets: A with extruded soya bean and B with bitter lupin + field bean + high protein pea. In the field trial the Italian sweet lupin varieties (Multitalia) were the most interesting for CP production and pea the best for yield. The feeding trial provided that the protein content was higher for the A diet (with soya bean) while fat, somatic cells and urea content did not differ