AbstractPlant sterols were found by gas liquid chromatography in the sterols of five species of aquatic vertebrates; mackerel (Scomber japonicus), rainbow trout (Salmo gairdnerii), smelt (Osmerus dentex), sardine (Sardinops melanosticta) and chimera (Chimera phantasma). The sterols of chimera liver, sardine flesh and sardine viscera contained 9.0, 2.4 and 3.1% of C28 and C29 sterols in addition to 86.7, 96.6 and 95.2% of cholesterol. The occurrence of norcholestandienol, campesterol, β‐sitosterol and C28 stanol was shown by combined gas chromatography‐mass spectrometry. Sperm whale (Physeter catodon) sterols consisted of more than 99% cholesterol with only traces of 22‐dehydrocholesterol.