In the present study, simultaneous voltammetric determination of noscapine and papaverine as two important alkaloids in opium was studied for the first time. A carbon paste electrode modified with multi-walled carbon nanotubes (MWCNTs) and TiO2 nanoparticles (TiO2/NPs) (MWCNTs/TiO2/NPs/CPE) was used for this purpose in the presence of cetyltrimethylammonium bromide (CTAB). Electron transfer rate of [Fe(CN)6]3–/4– as a redox couple probe on the surface of the MWCNTs/TiO2/NPs/CPE was studied using electrochemical impedance spectroscopy (EIS). The modified electrode preserved and combined the properties of the individual modifiers synergistically. A significant enhancement in the peak current responses of noscapine and papaverine were observed at the modified electrode compared to the bare electrode. Also, the peak currents of noscapine and papaverine were increased in the presence of CTAB. Under the optimal conditions, the peak current of differential pulse voltammograms was linearly dependent on analyte concentration in the range of 4–600 µM for noscapine and 5–400 µM for papaverine. The limit of detection (LOD) for noscapine and papaverine were 3.5 and 4.6 µM, respectively. Finally, this method was also applied for the determination of noscapine and papaverine in real samples.