A-nor sterols have been isolated and characterized from the marine sponge Teichaxinella morchella using High Performance Liquid Chromatography, Nuclear Magnetic Resonance, and Mass Spectrometry. A cell free extract of T. morchella was used to determine the biosynthetic origin of the sterols. Incubation experiments with radiolabled Farnesyl Pyrophosphate and cholesterol showed that the sterols are coming from a dietary source. Subcellular localization studies showed that the sterols are part of the cell membrane.