In the present study, 45 sea cucumber samples of the genus Holothuria with an average weight of 275 grams were caught in the winter season from a depth of 5 to 10 meters in the waters of Qeshm Island and extraction was performed using n-hexane (non-polar), diethyl ether (semipolar), and methanol (polar) solvents .The bioactivity of the extracts against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis and Staphylococcus aureuss were assessed. The n-hexane extract of Holothuria sp. induced a MIC of 1000 on the gram-negative E. coli and 300 mic/mL on the gram-positive B. subtilis and S. aureus. The MBC of this extract was 2000 μg /mL on E. coli and 1000 μg /mL on B. subtilis and S. aureus. Diethyl ether extract induced a MIC of 300 on the gram-positive B. subtilis and a MIC of 500 on the gram-positive S. aureus. The MBC of thic extract was 1000 μg /mL on B. subtilis and S. aureus. The methanol extract showed an MIC of 2000 μg /mL on the gram-positive B. subtilis and S. aureus. Amoxicilline as a positive control induced MIC and MBC effects on all the bacteria. In conclusion, the results indicated higher antimicrobial properties of n-hexane extract (non-polar) compared with diethyl ether and methanol extracts and revealed that the gram-negative bacteria especially P. aeruginosa were more resistant to the extracts compared with the gram-positive ones.