Аннотация:Investigation of the organic extract of a Red Sea sponge, Callyspongia sp., resulted in isolation and identification of three new C(22)-polyacetylenic alcohols, callyspongenols A-C (1-3), together with dehydroisophonochalynol (4). The structures of 1-3 were determined by 1D and 2D NMR studies and mass spectral determinations. Compounds 1-4 showed moderate cytotoxicity against P388 and HeLa cells.