: Endophytic fungi is a species of fungi which life on plant tissue system. Endophytic fungi can be isolated from the roots, stems and leave of the plant. Endophytic fungi can produce a substance potencial to be antibacteria. This research aimed to test the presence of antibacterial effect on an isolated leaf of mangrove plant Sonneratia alba towards Staphylococcus aureus and Escherichia coli. The method that is used for the antibacterial activity test, done by putting mycelia of endophytic fungi in combination media that has been smeared with Staphylococcus aureus and Escherichia coli. Obtained from research that has been made, it conducted two species of endophytic fungi that isolated from mangrove plant leaf Sonneratia alba. Both endophytic fungi has effect as antibacteria against Staphylococcus aureus and Escherichia coli, but the second type of endophytic fungi has more effective and stronger antibacterial effect compare to endophytic fungi type I and positive control