Double-stranded short-chain DNA was covalently bound to hemin, and was incorporated into the heme pocket of apo-myoglobin. Then this was further modified with activated poly(ethylene oxide). Thus, prepared PEG-Mb(DNA) was soluble and electrochemically redox active in PEG oligomers. Enhancement of the electron transfer reaction was not observed for the mixture of PEG-Mb and long-chain DNA. However, the charge of PEO-Mb(DNA) was found to be larger than that of PEG-Mb in PEG oligomer. It was suggested that the short-chain DNA was effective to be a molecular wire in the PEG.