Endophytic microbes (fungi or bacteria) contained in plants do not cause visible damage, and are capable of producing secondary metabolites according to their host plants. Endophytic fungi in vitro produce active metabolites that can function as antibacterial, herbicidal and natural pesticides. One of the plants that has been studied previously is that endophytic fungi are langsat (Lansium domesticum) (Fety, 2015). Stems of langsat contain flavonoids, saponins, tannins, and triterpenoids which are thought to be antibacterial compounds. The aim of the study was to isolate the endophytic fungi of antibacterial stem bark against Staphylococcus aureus and Escherichia coli. This study used the isolation and agar diffusion method (Kirby Bauer). The results obtained were 2 endophytic fungi isolates; isolate I is Rhizopus sp. and isolate II, namely Aspergillus sp. The antibacterial potential test of isolates I and II isolates against Staphylococcus aureus and Escherichia coli each had an average inhibition zone diameter of 15.67 mm; 11.67 mm and 17.76 mm; 21.93 mm. Based on the results of the study, the two endophytic fungi isolates on langsat bark have the potential as antibacterial against Staphylococcus aureus and Escherichia coli.