Powder samples of the TiO2-VO2 system have been studied by DTA, X-ray powder diffraction and magnetic susceptibility measurements. A phase diagram displaying several phases with rutile or rutile related structures is presented. The magnetic susceptibility measurements showed that nonmagnetic vanadium-vanadium bonds form at low temperatures over the entire range of composition. These bonds rupture in a temperature interval too narrow to be explained only bv antiferromagnetic Heisenberg interaction. Interaction between the nonmagnetic metal-metal pairs must be considered in order to explain the temperature dependence of themagnetic susceptibility