Two field experiments were carried out at the Experimental Research Station, Faculty of Agriculture, Moshtohor, Benha University, Qalyoubia Governorate, Egypt, during 2016/2017 and 2017/2018 seasons, to study the effect of foliar application of  benzyladenine (BA at 50 and 100ppm) and yeast extract (at 100 and 200 ml/L) in which were applied three times (50, 70 and 90 days after sowing) on growth, root yield characteristics and chemical compositions of sugar beet plant (Beta vulgaris L. cv. Ras-Poly). The obtained results indicated that, the foliar application with different applied treatments of both benzyladenine and yeast extract significantly increased all vegetative growth characteristics of roots (i.e. root length, diameter, fresh and dry weights/ plant) and leaves(i.e. leaves number, total leaves area/ plant and fresh and dry weights/ plant) at 110 days after sowing).The results also indicated that the foliar application of these treatments significantly increased root yield characteristics and quality  at harvest time compared with control plants in both seasons. Data also showed that, foliar spraying of BA at 100ppm and yeast extract at 200 ml/L increased photosynthetic pigments, minerals contents, total carbohydrates and crude protein content in sugar beet leaves at 110 days after sowing. Results also gave the highest values of all studied vegetative growth and root yield characteristics as well as root quality in this study. Hence, it could be concluded that foliar application of benzyladenine (BA) at 100 ppm and yeast extract at 200 ml/L have promoting effect on growth, root yield and quality of sugar beet plants.