An electrophoretic medium comprises at least one electrically charged particle dispersed posed in a fluid. The electrically charged particle comprises an inorganic black pigment having a surface area of at least about 7 m2/g. Preferred pigments are magnetite and mixed metal oxides containing two or more of iron, chromium, nickel, manganese, copper and cobalt, for example copper iron manganese oxide spinel and copper chromium manganese oxide spinel. The inorganic black pigment may bear a polymer coating.