A direct and simple method has been proposed to immobilize carcinoembryonic antibody (anti-CEA) on the surface of nanogold-modified glassy carbon electrode. Colloidal An was electrodeposited onto the surface of pretreated glassy carbon electrode (GCE) as immobilization matrix to amplify response signal, then anti-CEA was absorbed on nanogold by amino group and physical absorption. The impedance change occurred on the sensor surface due to the specific immuno-interaction was utilized to determine carcinoembryonic antigen (CEA). Tests revealed significant change in the electron-transfer resistance (R-et) to various concentration of CEA in Fe(CN)(6)(3-/4-) probe solution. The assay also demonstrates that the immunoelectrode exhibits a high level of sensitivity and satisfied response range.