Two pots experiments were carried out during two successiveseasons of 2003/2004 and 2004/2005 at Faculty of Agriculture,Fayoum University to study the response of Egyptian lupine plantcv. Giza 2 grown in calcareous soil to foliar application with activedry yeast at different concentrations. Plants were sprayed threetimes with yeast concentrations of 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7and 0.8%. The obtained results during the two studied seasonsrevealed that, growth characters of Egyptian lupine plant cv. Giza 2,i.e., plant height, root length, number of leaves /plant, leaf area,number of branches /plant and fresh as well as dry weights weresignificantly increased at active dry yeast concentrations over 0.1%comparing to those of unsprayed plants. The maximum growthvalues were attained at concentrations of 0.5%. Yield and most itscomponents represented by peduncle length, number of pods,number of seeds, weight of pods, weight of seeds and seedsyield/plant as well as weight of 100-seeds were also increased atactive dry yeast concentrations higher than 0.1%. However theenhancement growth characters due to yeast application was moreobserved from anatomical studies. Where sections diameters ofroots, stems and leaf petiole were increased, resulting fromincreasing phelloderm thickness and diameter of vascular cylinderfor root; average cortical cell diameter, thickness of vascularcylinder for stem and vascular bundle dimensions for leaf petiole.Also medvein and blade thickness were increased in plants sprayedwith yeast especially at concentrations higher than o.5%. Suchincreases resulted from increasing palisade and spongy tissuesthickness and vascular bundle dimensions. Yeast application hadstimulatory effect on N.P.K, chlorophyll a, b and carotenoidsconcentrations in Egyptian lupine leaves and total carbohydrates,total N, protein and total alkaloids in dry seeds.