Multiwalled Carbon Nanotubes (MWCNTs) were used as a support of amperometric enzymatic biosensors of guaiacol. The structural quality of MWCNTs was determined for Raman Spectra and DRX analysis. MWCNTs were decorated with iron oxide nanoparticles (36 w/w%), which were observed by FE-SEM, and were confirmed by with EDX, and TGA analysis. Laccase enzyme (aspergillus sp.) was immobilized on the surface of MWCNTs (oxidized and decorated with iron oxide nanoparticles) confirmed by XPS analysis and used to amperometric detection of guaiacol. The material obtained was deposited on the active surface of glassy carbon electrode (GCE) and was carried out using a typical three-electrode system with saturated calomel electrode as a reference and a graphite rod as a counter-electrode. The results confirm the potential use of bioelectrode Lac/MWCNTs/GCE and Lac/Fe3O4/MWCNTs/GCE for the guaiacol detection in low concentrations. Amperometric sensitivities and detection limits of Lac/Fe3O4/MWCNTs/GCE bioelectrode (110.186 μA mMcm−2 and 34.301 nM for reduction current respectively) showed better results than Lac/MWCNTs/GCE bioelectrode in a linear range 0–0.066 μM of guaiacol.