The present work was carried out during the two seasons of 2019 and 2020 in Al-Marashda Research Station, Qena Governorate, Egypt. This experiment was conducted to examine the possibility of producing Melia azedarach L. as a valuable trees under salinity stress by using yeast extract levels as bio fertilizers. The layout of the experiment was sitting as completely randomized in a split- plot design with two factors (salinity and yeast extract with two controls) and included 16 treatments; 4 levels of salinity (0, 2000, 3000 and 4000 ppm) and 4 levels of yeast extract (0, 5, 10 and 15%). Results indicated that the different vegetative growth characters as well as chemical constituents of M. azedarach were decreased due to various salinity concentrations. Foliar application of yeast extract with salinity levels increased of vegetative characters and chemical composition compared to the control. Meanwhile, the exogenous application of yeast extract showed a significant reduction in values of free proline content in leaves of M. azedarach and this decrease was higher with spraying 15%, in the average of seasons. These results assure the possibility of growing M. azedarach seedlings at the same conditions of salt stress by the use of some bio fertilizers as yeast. Accordingly, these trees can be planted in newly reclaimed soils and afforestation programs in areas that affected by salinity with spraying by yeast extracts at 15%.