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We demonstrate fully inkjet-printed graphene-gated organic electrochemical transistors (OECTs) on polymeric foil for the enzymatic-based biosensing of glucose. The graphene-gated transistors exhibit better linearity, repeatability, and sensitivity than the printed silver-gated devices studied in this work and other types of printed devices previously reported in the literature. Their limit of detection is 100 nM with a normalized sensitivity of 20%/dec in the linear range of 30–5000 μM glucose concentrations, hence comparable with state-of-the-art OECT devices made by lithography processes on rigid substrates and with complex multilayer gates. Electrochemical impedance spectroscopy analysis shows that the improved sensitivity of the graphene-gated devices is related to a significant decrease of the charge-transfer resistance at the graphene electrode–electrolyte interface in the presence of glucose. The optimized …