Recently, copper, silver, and gold-enhanced colloidal gold have been reported for immunoglobin G (IgG) determination, which is the model of electrochemical immunoassay with low detection limits ranged from 1.0 ng/mL to 0.25 pg/mL [19–21]. The metal-enhanced colloidal gold electrochemical stripping metalloimmunoassay combines the high sensitivity of stripping metal analysis with the remarkable signal amplification resulting from the catalytic precipitation of metals onto the gold nanoparticles [21–23]. Among these metals, the copper-enhanced protocol is better than the other metal-enhancing protocols because the copper-enhancer solution, which contains ascorbic acid and copper sulphate, is easy to prepare and preserve. Furthermore, the copper determination by anodic stripping voltammetry is simple, and highly sensitive. Willner and co-workers also applied the catalytic deposition of copper on gold nanoparticles for NADH detection [24]. However, metal-enhanced colloidal gold has not been previously applied to the detection of bacterial cells in real samples, especially for the detection of S. typhi. Therefore, we have employed the electrochemical stripping metalloimmunoassay based on a copperenhanced gold nanoparticle label for the determination of S. typhi in real samples for the very first time, which will be useful in the diagnosis, follow-up treatment, and controlling in advance the epidemic disease of typhoid fever.