Background: Seagrasses are an important component of Nearshore marine ecosystems and a rich source of secondary metabolites with important pharmacological properties. Materials and Methods: In this work, crude hydroethanolic extract and chloroform fraction (SfCHCl3) from marine plant Syringodium filiforme were evaluated for antimicrobial and cytotoxic potentials. In addition, the chemical composition of chloroform fraction was determined by gas chromatography-mass spectrometry (GC-MS) analysis. Results: GC-MS analysis allowed the identification of 68 compounds in the SfCHCl3, where palmitic acid (39.18%) was the main component. The evaluation of antibacterial activity of SfCHCl3 showed good activity against strains of Staphylococcus aureus (ATCC 6538), Pseudomonas aeruginosa (ATCC 9027), and Salmonella typhi (ATCC 9992v), and it was less active against Escherichia coli (ATCC 10576) and Candida albicans (ATCC 10231), while the crude extract showed low antibacterial activity. Furthermore, an important cytotoxic effect of SfCHCl3 in the A549 human lung carcinoma cell line was evidenced, which were similar to the cytotoxicity of cisplatin in the same cell line. Conclusion: The results suggest that compounds may play an important role in the antimicrobial and cytotoxic effects observed for this species. In addition, this research contributes to the chemotaxonomic characterization of S. filiforme and validates this species as a potential source of natural antimicrobial and cytotoxic molecules.