Aqueous, ethanol, methanol and acetone stem bark extracts from nine tree species; Pinus halepensis, Leucaenia leucocephala, Ficus sycomorus, Quercus ruber, Albizia lebbeck, Terminalia arjuna, Bauhinia variegate, Cassia fistula and Kegelia africana growing in Assiut, Egypt were investigated for their antimicrobial activity against three bacterial and three fungal species in vitro as well as their antioxidant activity using DPPH radical scavenging. Patterns of inhibition varied with the plant extract, the solvent used for extraction, and the organism tested. Acetone extract of K. africana gave the maximum significant inhibitory effect against the three bacterial strains. Bacillus cereus was the most inhibited bacteria, followed by Erwinia carotovora. The maximum antifungal activity was noticed in different extracts of C. fistula against the three fungal strains; Fusarium oxysporum, Fusarium solani and Rhizoctonia solani with significant differences comparing with the other extracts. Samples extracted by acetone and ethanol, respectively, showed significant increment in antibacterial and antifungal activities over either methanol or aqueous ones, which recorded the minimum inhibition. The methanol extract of both K. africana and B. variegate showed the strongest inhibition of DPPH radical activity. The EC50 reached its lowest values with acetone extract of A. lebbeck followed by ethanol and acetone extracts of P. halepensis.