Carbon electrode materials have the unique advantages of being low-cost, being easily manufactured, and exhibiting good electronic conductivity and high thermal and chemical stability [1]. Carbon exhibits a good choice for solid screen-printed electrodes that can be readily utilized in electrochemical biosensing. In particular, within this work, the surface of carbon screen-printed electrodes with a diameter of 2mm was modified with Au nanoparticles via electrodeposition for the immobilization of aptamers [2,3]. For this purpose, Au-thiolated aptamers were selected, and the route of chemisorption was followed, to allow the formation of a covalent bond with the Au nanoparticles. After the aptamer was immobilized, the system was used for the detection of tetracycline (TET). In particular, a concentration of 1μM aptamer was incubated on the Au-sensitized carbon working electrode (WE), followed by 0.1mM of Mercaptohexanol (MCH), and these were left overnight. Following that, different concentrations (5nM to 1000nM) of TET were used. Differential pulse voltammetry was performed using a Ag/AgCl reference and a Pt wire as a counter. The results yielded a limit of detection of the order of 10^-9nM. It can be noted that the aptasensor developed in this study can potentially be used for the detection of tetracycline in pharmaceutical preparations, drinking water, and contaminated food samples such as milk.