A research on antimicrobial activity testing of the endophytic fungi which was symbiosis with mangosteen (Garcinia mangostana L.) has been conducted. About fourteen isolates of fungi from mangosteen have been isolated. Each fungal isolates were fermented in liquid medium of soybean extract broth for one week on a rotary shaker incubator at temperature of 25-27 oC and speed of 90 rpm. Each fermentation of fungal isolates were tested their antimicrobial activity against microbes Staphylococcus aureus, Escherichia coli and Candida albicans with the agar diffusion method. There were two fungal isolates that active against Escherichia coli and three fungal isolates that active against Staphylococcus aureus.
