Biodiesel is a renewable fuel composed by alkyl esters extracted from vegetable oils and/or animal fats. Due to its composition, it is susceptible to oxidation reactions, which affect quality and suitability use of the fuel. In order to prevent some of these oxidation problems and ensure the product suitability covering quality requirements, biodiesel producers have used synthetic antioxidants in their production processes. Here we used gas chromatography with flame ionization detector to develop an analytical method to determine synthetic antioxidants in final biodiesel. The development stages covered method optimization, limitations evaluation and the method validation according to international protocols and suitable statistical parameters. The recovery values were between 92 and 106%, and uncertainty of measurement has presented a shift from 1 up to 40% in the application range. Considering that in Brazil soybean oil is responsible for about 80 % of all raw materials used in biodiesel production, the method is very useful. In worldwide level, as canola and corn have a significant unsaturated ester composition, as soybean, the method is also applicable.