The field emission display is a flat panel display in which electrons are emitted from an array of field emission cathodes, accelerated across a vacuum gap, and form an image on a hat phosphor screen. Diamond-like carbon is a strong candidate for field emission microcathodes in such displays because of its low electron affinity and chemical inertness. The field emission properties of various types of diamond-like carbon such as a-C:H and ta-C are reviewed and the origin of the low electron affinity of diamond and diamond-like carbon is discussed.