In this paper the detection method of fat-soluble vitamins and their related compounds by thin layer chromatography is described, using Kieselgel G and Aluminium oxid G as the chromatographic plates, and chloroform and benzene as the solvents for development. For the detection after chromatographic separation, 60% perchloric acid, 95% sulfuric acid, 65% nitric acid, antimony trichloride reagent and Emmerie-Engel reagent were used. 95% sulfuric acid proved to be universal detection reagent for all the fat-soluble vitamins separeted by this method. This method is advantageous because of being able to use sulfuric acid and perchloric acid as detection reagent, and because of taking shorter time than paper partion chromatography for the separation of fat-soluble vitamins.