This chapter reviews what is known about the fate of carbon during early differentiation of inner solar system planets. It reviews the nature of carbon fractionation in a magma ocean as compared to the core, mantle, and atmosphere, and how this may have varied between planetary bodies in the solar system. It discusses whether magma ocean processes could have established the present-day budget of carbon in Earth’s bulk silicate, and also reviews possibilities for the early temporal evolution of the mantle carbon budget through core formation, later veneer addition, and magma ocean crystallization processes.