ABSTRACT In this work, a sensitive electrochemical sensor is provided for hydroxylamine, by Fe3O4@CuO core-shell nanocomposite on the screen printed graphite electrode (SPGE) surface. Fe3O4@CuO core-shell nanocomposite was prepared by simple method and characterised by transmission electron microscopy (TEM), scanning electron microscopy (SEM), vibrating sample magnetometry (VSM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). The modification of sensor was performed by drop-casting process. Electrochemical investigations showed that the fabricated Fe3O4@CuO/SPGE sensor exhibited excellent catalytic performance for the oxidation of hydroxylamine. The Fe3O4@CuO/SPGE exhibited good electrocatalytic performances towards hydroxylamine by using differential pulse voltammetry (DPV) with a sensitivity about 0.1439 μA μM−1 and a low limit of detection (LOD) (6.0 nM) in the linear range of 0.01–340.0 μM. In addition, the Fe3O4@CuO/SPGE showed an acceptable repeatability, reproducibility and stability in the detection of hydroxylamine. Finally, the practical utility of this new sensor was substantially revealed for detecting hydroxylamine in different water samples.