Four strains of Phyllosticta were selected to study their antimicrobial activities. The tested strains were identified as Phyllosticta capitalensis, P. citriasiana, and P. cordylinophila based on the internally transcribed spacer (ITS) sequences and morphologies. Initially, the fungal strains were cultured on the potato dextrose agar (PDA) and cultivated at 27• C for 3 weeks. After incubation, the fungal metabolites were extracted using ethyl acetate. The crude extracts were then concentrated using evaporation and subsequently used in antimicrobial activity assay. Our results showed that these fungal crude extracts could inhibit the growth of Escherichia coli, Bacillus cereus, and Pseudomonas aeruginosa but were not active against Aspergillus niger.