Bioactive compounds of gonad, respiration tree, cuvierian organ, and body wall of the sea cucumber Holothuria leucospilota collected from the north coast of the Persian Gulf were extracted using ethyl acetate, methanol and water–methanol solvents. Extracts were evaluated for their antibacterial and antifungal activities against Aspergillus niger, Candida albicans, Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli. The activity was determined using the disc diffusion test. Cytotoxic activities of the extracts were determined by brine shrimp lethality assay. Results demonstrated that the A. niger was shown to be the most sensitive microorganism followed by C. albicans. The inhibition zone against A. niger and C. albicans had minimum inhibitory concentrations ranging from 3 to 7 μg/ml. The highest antifungal activity was found in G (water–methanol) with an inhibition zone of 50 mm against A. niger at 18 μg/ml extract concentration continuing with CT (methanol) with 46 mm inhibition zone against A. niger at 18 μg/ml extract concentration. The highest cytotoxic effect of methanol extract was found with LC50 values of about 40.31 μg/ml in the gonad organ from H. leucospilota continuing with the respiration tree organ with LC50 values of about 72.49 μg/ml.