AbstractIn the course of isolating and analyzing the fatty acid methyl esters (FAME) from steelhead trout (Salmo gairdneri) eggs and sac fry, a component was found on gas liquid chromatography to have a retention time longer than any characteristic polyunsaturated fatty acid previously encountered in trout. Subsequent purification and analysis demonstrated this component to be cholesterol. Thus, cholesterol and related compounds can interfere in the analysis of FAME when the methyl esters are prepared by transesterification.