The application of the Vierordt’s and the first derivative at the “zero crossing” methods was evaluated for the simultaneous determination of synthetic food dyes Yellow “sunset” (E110) and Ponso 4R (E124) in model solutions. The concentrations interval of components is established at which the principle of optical densities additivity is observed. For the implementation of the Vierordt’s method, wavelengths with the maximum difference in the absorption coefficients of the individual components (470.2 and 536.7 nm) were chosen. The influence of the differentiation step at various concentrations of dyes on the magnitude of the first derivative corresponding to the absorption maximum in the spectrum of zero order was studied. The values of the “zero intersections” for the first derivatives of the absorption spectra of individual compounds were determined at the optimal differentiation step ?? = 2 nm, which amounted to 482.5 nm and 507 nm for Е110 and Е124, respectively. It was established that the error in the determination of individual dyes by the method of derivative spectrophotometry is lower than by the Vierordt’s method. The correctness of the dyes determination by the Vierordt’s method varied for E110 from 102 to 105%, for E124 from 93 to 107%. The correctness of the determination by the first derivative method with “zero crossing” varied for E110 from 98% to 101%, for E124 from 96% to 103%.