The main objective of the study was to observe the antioxidant, cytotoxicity and anticancer activity of 12 marine endophytic fungi extracts. Marine endophytic fungi were isolated from 11 species of seaweeds, collected from Kovalam (covelong), Chennai and Mandapam, Ramanathapuram district in Tamil Nadu, India. The isolated fungi were extracted with ethyl acetate solvent for bioactivity assay. DPPH assay was performed for antioxidant study. The extracts from Chaetomium sp., Phomopsis sp., Acremonium sp., Aspergillus niger, Xylaria sp., Cladosporium sp., and Fusarium sp., showed greater antioxidant potential compared to other fungal extracts. The cytotoxicity assay was carried out in the Vero cell line and the anticancer activity was found in HEp2 cell line (Human Epidermoid carcinoma cells) and in A549 cell line (Human Lung Carcinoma – Epithelial cells). We observed that Phomopsis sp. fungal extract was more toxic to both the cancer cells, but, comparatively, the same extract exhibited less toxicity against the normal Vero cells. The IC50 values for other 11 different fungal extracts against Vero cells were lesser than the IC50 value of the respective extract against A549 cancer cells, indicating the toxicity of these 11 different fungal extracts.