8-hydroxy-7-iodo-5-quinoline sulfonic acid (HIQSA) was determined using square wave anodic stripping voltammetry (SWASV) at the surface of carbon paste electrode modified with Sb2O3 and multi-walled carbon nanotubes-titanium dioxide nanohybrid (Sb2O3/TiO2-MWCNTPE) in aqueous media. To estimate the properties and morphology of the modified electrode, field emission-scanning electron microscopy (FE-SEM) coupled by energy dispersive spectroscopy (EDS) was applied. The linear concentration range was found to be 1.0 to 100 μM by using accumulation potential of −0.8 V and accumulation time of 150 s. Under these conditions, LOD and LOQ were obtained at 1.2 and 3.9 μM, respectively. This newly developed method was successfully applied for the determination of HIQSA in tap water.