An electromagnetic noise suppression sheet obtained by using combination of a conductive carbon and spinel ferrite particles having a cumulative 50% volume particle diameter of 1 to 10 μm, can exhibit an excellent transmission attenuation power ratio and a reduced return loss in a near electromagnetic field, and is suitable for high-density mounting. The electromagnetic noise suppression sheet of the present invention can be produced by the process of the present invention which includes the steps of applying a coating material in which the conductive carbon and the spinel ferrite particles having a cumulative 50% volume particle diameter of 1 to 10 μm are dispersed, to form a coating film having a thickness of 10 to 100 μm after dried, and subjecting the resulting coating film to thermoforming under pressure.