Venlafaxine (VF) is an arylalkanolamine serotonin–norepinephrine reuptake inhibitor (SNRI) and is used primarily for the treatment of major depression in adults. The chemical structure of VF was shown in Fig.1. Fig. 1. The chemical structure of venlafaxine Literature reveals that, several methods including voltammetry [1], high-performance liquid chromatographic (HPLC) [2], liquid chromatography–tandem mass spectrometry (LC–MS–MS) [3], headspace-solid phase microextraction (HS-SPME)- gas chromatography (GC) [4] and nonaqueous capillary electrophoresis- mass spectrometry [5]. However, these methods face the drawbacks of being expensive, laborious and require pre-treatment of the samples. Chemiluminescence (CL) is generally defined as the emanation of light (ultraviolet, visible or infrared) through the process of a chemical reaction. CL detection has advantages including simplicity of operation, low cost of instrumentation, high selectivity, wide dynamic range, reproducibility and rapidity. In this work, CuO nanoparticles (CuO NPs) were prepared by using quick precipitation method. Then, those were characterized by using X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The results of experiments revealed that CuO NPs amplified the intensity of H2O2–NaHCO3 CL system. Moreover, it was found that VF quenched the CuO NPs–H2O2–NaHCO3. Based on these results, a new and sensitive CL method for determination of VF was stablished. After optimization of reaction condition, the calibration curve was drawn for VF. The liner range and limit of detection of the CL method were 5.0 × 10−6 – 5.0× 10−4 mol L−1 and 4.1 × 10−6 mol L−1, respectively. The method was successfully exploited for measurement of VF in the pharmaceutical preparations.