This paper gives a description of a high-speed X-ray tomographic technique and the results of its application to finding the density distribution of detonation products of condensed explosives from measurements using synchrotron radiation. The data obtained for a cylindrical charge of pressed TNT of diameter 12.5-mm and density 1.6 g/cm 3 are compared with the results of solution of the corresponding gas-dynamic problem of steady-state detonation. The experimental and computational results are in satisfactory qualitative and quantitative agreement. The features of the employed technique and the distribution obtained are analyzed. The technique as a whole and the results obtained can be used to test and refine the known equations of state for detonation products and to construct new ones.