Here a new electrochemical immunoassay platform has been developed for the trace amounts of myelocytomatosis (c-Myc) oncoprotein detection to solve the urgent need for improved early diagnostic tools of cancer. To our knowledge, this is the first electrochemical immunosensor for c-Myc oncoprotein determination by employing gold nanoparticles as labels in a signal enhancement strategy. It is based on a sandwich immunoassay where the target c-Myc oncoprotein (CAg) is captured by the primary c-Myc antibody (CAb) modified on gold substrate, followed by adding another CAb conjugated to gold nanoparticle tags. The proposed sensor shows a linear range between 4.3pmolL−1 and 43nmolL−1, with an estimated detection limit of 1.5pmolL−1. The recovery was achieved between 96.2% and 109% in 1% serum samples. This sensitive immunosensor holds great promise for the early diagnostic application of cancer at a curable stage.