  The fundamental measure density functional theory for hard spheres is
generalized to binary mixtures of arbitrary positive and moderate negative
non-additivity between unlike components. In bulk the theory predicts
fluid-fluid phase separation into phases with different chemical compositions.
The location of the accompanying critical point agrees well with previous
results from simulations over a broad range of non-additivities and both for
symmetric and highly asymmetric size ratios. Results for partial pair
correlation functions show good agreement with simulation data.
