Minute amounts of metallic as well as non-metallic inclusions significantly affect both bulk and surface properties of the electroplated gold films being used by the electronics industry. Surface effects are caused by the presence of extraneous materials diffused out from the interior to the surface, while bulk effects are brought about by the influence of inclusions on the microstructure of the gold films. This article reviews the current status of understanding of such inclusion effects in both soft and hard gold: these play essential roles in the fabrication of today's microelectronic devices.