Grass-Iegume mixtures have a great economic importance mainly due to the fact that these cultures can storage huge quantites of N without any negative effects on production, being also able to determine an increase in forage nutritional value. This study aims to evaluate the behavior of the mixture consisting in Medicago saliva, Lolium hybridum, Festuca arundinacea and Dacyls glomerata under the influence of mineral fertilization, in the soll-climatic condition specific to Transvlvania Plateau, Romania. The experience was established in the spring of 2012, according to the subdivided parcels method, in 8 variants with 4 replications. The mixture was seeded on two different distances between roads, namely 12.5 cm and 25 cm. Four treatments (doses) with mineral fertilization were performed: V1��-control variant, unfertilized, V2-N50P60K80, V3-N75P60K80, V4-N100P60K80. In order to accomplish the objective proposed which is to provide a deep and comprehensive anaysis of the forage mixture studied, data related to green mass and DM production and floristic composition are given. This paper summarizes the results registered on 2013. The seeded forage species had a good response to this specific mixture and to the climatic conditions. The results showed that mineral fertilization with N has a significant influence both on species green mass and DM production and on their floristic composition.