By extrapolating the experimental laws describing the energy confinement and the magnetohydrodynamic stability limits in current large tokamaks, it can be shown that stable thermonuclear ignition equilibria should exist in this type of configuration if the product of dimensions multiplied by a power of the magnetic field intensity is large enough. By quantitatively applying this result to several next-generation tokamaks, it appears that such equilibria could exist in these machines. Moreover, the additional heating power that will be available in these devices should be sufficient for ignition.