This paper reports the production of a novel magnetic nanocomposite based on multi-walled carbon nanotubes (MWCNTs) decorated with magnetic coreshell Fe 3 O 4 @SiO 2 nanoparticles which were used to f a b r i c a t e a m o d i f i e d c a r b o n p a s t e e l e c t r o d e (Fe 3 O 4 @SiO 2 /MWCNT-CPE). The Fe 3 O 4 @SiO 2 / MWCNT-CPE was investigated for the simultaneous determination of sunset yellow (SY) and tartrazine (TT) in 0.1 mol/L phosphate buffer solution (pH 6.0) using square wave voltammetry (SWV). The synthesized nanocomposite was characterized by transmission electron microscopy, scanning electron microscopy, energy dispersive spectroscopy and Fourier transform infrared spectroscopy. The proposed electrode exhibits linear ranges of 0.5-100 μmol/L SY and TT with detection limits of 0.05 and 0.04 μmol/L for SY and TT, respectively. The novel proposed voltammetric method was successfully applied in the simultaneous determination of SY and TT in food products, with results similar to those obtained using a HPLC method at 95 % confidence level.