In this study, a novel method was developed to fabricate a glassy carbon electrode (GCE) modified by a composition of multiwalled carbon nanotubes (MWCNTs) and Fe3O4@MCM-48-SO3H nanoparticles (MWCNTs-Fe3O4@MCM-48-SO3H/GCE) as a sensitive anionic composite layer for simultaneous determination of norepinephrine (NE) and tyrosine (Tyr) in the presence of ascorbic acid (AA). Electrochemical behavior of the electrode was studied using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) and chronoamperometry (CA) techniques. Under the optimum conditions, the modified electrode provides a linear anodic peak versusNE concentrations in the range of 0.4–600 μMwith a detection limit of 0.19 μMand Tyr concentrations in the range of 0.9–400 μMwith a detection limit of 0.28 μM, respectively, using the differential pulse voltammetry method. The modified electrode has been successfully applied for the determination of NE and Tyr in real samples.