The extracts from the starfish Asterina pectinifera obtained using various organic solvents and distilled water were tested for their antimicrobial activities against fungi and yeasts. The methanol and water extracts were found to be the most active and Aspergillus spp. and Cryptococcus neoformans proved to be sensitive species. The extracts are polar, stable to a wide range of pH and a high temperature, and possess a very distinctive UV spectrum. The colour reactions for functional groups of antimicrobial substances indicate the presence of some distinctive chemical properties common to steroidal oligoglycosides which results suggest that the antimicrobial activity is due to structures common to steroidal oligoglycosides.