New C14surfactin methyl ester and eight earlier described surfactins were isolated from the marine bacterium Bacillus pumilus associated with zoantharia Palythoa sp. The structure of the compounds isolated was established based on the data from amino acid analysis, one and twodimensional NMR spectroscopy, and tandem nanoelectrospray mass spectrometry. The absolute configurations of amino acids were determined by Marfey's method. Cytotoxic activity of a number of surfactins with respect to the tumor cells HCT-116 and MDA-MB-231 was studied.