Here we report the fabrication of an electrochemical sensor for the simultaneous determination of the concentrations of omeprazole (OMZ) and lansoprazole (LAN) in biological fluids and pharmaceuticals in Britton-Robinson buffer solution (pH 6.0). The sensor was prepared by bulk modifying a carbon paste electrode with deep eutectic solvent (DES), followed by carrying out electropolymerization of Eriochrome Black T (EBT) at this electrode. The presence of DES increased the extent of the polymerization of EBT on the surface of the electrode, and this increase led to better OMZ and LAN electron transfer kinetics at the electrode surface. The modified electrode was evaluated and characterized by performing cyclic voltammetry, electrochemical impedance spectroscopy, scanning electronic microscopy, and Fourier-transform infrared spectroscopy. The best responses were obtained in drug-free Britton-Robinson buffer solution (pH 6.0) after 600 s of stirring at the open circuit potential. Linear relationships were obtained between the anodic peak currents and the concentrations of OMZ and LAN in the ranges of 0.010-0.276 and 0.010-0.300 μM, with detection limits of 0.006 and 0.009 μM, respectively. Satisfactory results were also obtained for the analysis of OMZ and LAN in real samples. The excellent sensitivity and easy regeneration and modification of this electrode with DES followed by the polymerization of EBT make this electrode relatively highly applicable for flow methods.