We study field emission from wide band gap metal-semiconductor nanocomposites. The grains of the wide band gap semiconductor are embedded into the layers of metal, Interfacial charge transfer gives rise to the metal-induced gap states (MIGS) in the vicinity of,the grains. If the density of the semiconductor grains is sufficiently large, MIGS hybridize with conduction band states of the semiconductor forming a quasi-band, which can be populated by the electrons from the metallic matrix through the scattering in the metal-semicondtictor composite. The location of the high-lying MIGS in the vicinity of the conduction band of the wide band gap semiconductor (e.g., diamond) significantly reduces the barrier between those states and the vacuum level compared to the work function of a metal. Thus low-threshold field emission from A nanocomposite becomes possible. This hypothesis is supported by Monte Carlo simulation of transport through a nanocomposite. (C) 2003 American Vacuum Society.