Results of joint photochemical-radiative equilibrium calculations for the mesosphere and upper stratosphere are presented. The major assumptions were that only oxygen allotropes participate in the chemistry and that the radiative balance is between absorption of solar radiation by molecular oxygen and ozone and infrared emission by carbon dioxide and ozone. Equilibrium temperatures and ozone concentrations for winter and summer were calculated by two methods: an iterative procedure assuming a steady state, and as the asymptotic limiting distributions of a marching problem. The second method gives lower temperatures than the first in the upper mesosphere because of the diurnal variations in ozone concentration.