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In the search for new natural, bioactive, and effective substances that have a favorable impact on health, many natural sources have long been exhausted. Endophytic fungi have been little studied for this purpose. This is the background to the present study, which involves testing and evaluating the antibacterial activity of mycoendophytes associated with Limoniastrum feei against 8 pathogenic bacterial strains for the first time. These include the following 4 gram-positive bacterial strains: Staphylococcus aureus, Enterococcus faecalis, Bacillus subtilis, and Listeria monocytogenes; and the following 4 gram-negative strains: Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia, and Salmonella typhimurium. The study was conducted in 2 phases. The first involved direct contact between 24 endophytic fungal species and 8 bacterial strains. In the second, a more resistant strain of Staphylococcus aureus (MRSA) was introduced. A total of 12 mycoendophyte extracts, selected from the 24 previously used, were tested using the disk diffusion method and compared to synthetic antibiotic discs. Fungal metabolites were extracted using hydroalcoholic methods. Two organic solvents were used: ethyl acetate and methanol. Bacterial strains showed variable sensitivity effects. According to the disk diffusion test, all of the ethyl acetate fungal extracts demonstrated inhibitory activity on the tested bacteria. The antibacterial activity of these extracts was comparable or superior to that of standard antibiotics. Conversely, the methanolic extracts showed minimal or no activity. We conclude that mycoendophytes represent a promising source of natural products with potential antibacterial therapeutic applications.