A non-enzymatic sensor for hydrogen peroxide (H 2 O 2) determination based on Ag/δ-FeOOH nanocomposite immobilized on an all-plastic disposable carbonbased electrochemical cell (DCell) is constructed by a rapid prototyping technique. Ag/δ-FeOOH is synthesized by a simple and reproducible method and its structural and morphological properties characterized by X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The Ag/δ-FeOOH is successfully immobilized on the DCell, as revealed by SEM images. The electrochemical investigation indicates that the Ag/δ-FeOOH/DCell has a good electrocatalytic response for the H 2 O 2 reduction, showing detection limit of 71 μmol L À 1 H 2 O 2 at a signal-tonoise ratio of 3 and analytical sensitivity of 215.4 μA mM À 1 cm À 2. Moreover, Ag/δ-FeOOH/DCell can be used to selectively detect H 2 O 2 in the presence of dopamine (DA), uric acid (UA), and ascorbic acid (AA). Finally, Ag/δ-FeOOH/DCell can be used to determine H 2 O 2 in fetal bovine serum. The achieved results indicate that the non-enzymatic Ag/δ-FeOOH/DCell is a costeffective alternative for the determination of H 2 O 2 .