TWENTY ONE endophytic species were isolated from 360 segments of Avicennia marina from two different locations of Red Sea mangrove forest in 2009 to 2010. Some of the endophytes were identified to genus or species level using traditional morphological methods, but most were classified as sterile mycelia. The isolated species belonged to 7 genera (Acromonium, Aspergillus, Chaetomium, Cladosporium, Fusarium, Phoma and Ulocladium). Thirty nine isolates of endophytic fungi were selected to detected their antagonistic abilities against Bacillus subtilis, Staphylococcus aureus, Micrococcus luteus, Escherichia coli, Aspergillus niger and Alternaria alternate. The obtained results indicated that some isolates of the same species showed different behavior against used bacteria , while few of these isolates of the same species showed the same behavior. The tested endophytic species did not show any antagonistic ability against Aspergillus niger and Alternaria alternate.