Formation and function of N2-fixing systems between bacteria from Rhizobiaceae family and legume plants from Fabaceae family are especially sensitive to molybdenum (Mo) deficiency. The hypothesis of the present work was that nitrogen fixation and assimilation in Mo deficient pea and alfalfa plants are enhanced when the nutrients were supplied through the foliage. It was established that foliar fertilization resulted in the increase of nitrogen fixation and biomass accumulation in the absence of Mo. The positive effect of foliar fertilization at insufficient Mo supply on the nitrogen uptake is better expressed in garden pea than in alfalfa. Otherwise, alfalfa was more sensitive to Mo starvation than the pea plants. Insufficient Mo supply leads to significant reduction in plant Mo content and nitrogen fixing activity, while stress induced free amino acids increased repeatedly. The negative effect of Mo exclusion from the nutrient media on nitrogen assimilation and biomass accumulation diminished through the foliar absorbed nutrients.