The densities of atomic carbon in the Venusian thermosphere are computed for a model which includes both chemistry and transport. The maximum density of C is 2.8¿107 cm-3 near 150 km for an assumed O2 mixing ratio of 1¿10-4. Photoionization of atomic carbon is found to be the major source of C+ above 200 km, and resonance scattering of sunlight by atomic carbon may be the major source of the C I emissions at 1561 ¿, 1657 ¿, and 1931 ¿. The computed C+ densities are found to be in substantial agreement with those measured by Pioneer Venus.