Ferrocene-polyamides having not only sequence discrimination ability but also a redox mediator were synthesized. The affinity and selectivity of these compounds for a DNA duplex having a cognate GCG sequence were investigated by CD spectroscopy. Furthermore, the binding of the ferrocene-polyamides to DNA duplexes immobilized to a gold electrode was detected by cyclic voltammetry (CV) experiments. The electrochemical studies revealed that the fully matched DNA duplex having a GCG sequence showed the largest electric current, and the introduction of a mismatch site decreased the current significantly. These results suggested the potential of the ferrocene-polyamide compounds as new electrochemical ligands for electrochemical SNPs detection.