In this work, a novel electrochemical sensor using a carbon paste modified electrode with CuO doped in ZSM-5 nanoparticles (CuO/ZSM-5 NPs/CPE) is successfully fabricated for simultaneous determination of hydrazine (HY) and hydroxylamine (HA). The prepared materials are characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (XRD), energy dispersive X-ray (EDX) and Brunauer–Emmett–Teller (BET) techniques. For sensitive determination of HY and HA, differential pulse voltammetry (DPV) and amperometry techniques are used. Furthermore, in amperometric measurements, the current response and the HY concentration have linear relationships in the ranges of 25 μM to 0.9 mM and 0.9–4.5 mM. Also, there are linear relationships in the ranges of 20 μM to 0.9 mM and 0.9–7.0 mM for HA. Also, low detection limits of 3.6 μM and 3.2 μM (S/N = 3) are achieved for HY and HA, respectively. The sensor has good stability, reproducibility and anti-interference capability as well as simplicity.