<p>A method for the quick detection and determination of biodiesel impurities in hydrocarbon fuels of different types is presented. This procedure is based on the analyzed samples components separation by thin-layer chromatography with elution by mixtures of polar and nonpolar solvents. The biodiesel fuel is detected in a chromatogram using a mixture of iron salts solutions. The biodiesel fuel detection range is from 0.1 to 100 vol. % with relative standard deviation from 0.07 to 0.2. Since the analytical procedure is simple and there is no need for complicated equipment, this method can be recommended for both well-equipped laboratories and non-laboratory conditions.</p>