An ionic liquid-type phosphomolybdic salt comprising 1-cetyl-3-methyl-imidazolium chloride (CMImCl) and 1:12 phosphomolybdic acid (PMo12) was prepared by solid state grinding. The new phosphomolybdic salt of CMIm-PMo12 was immobilized on glassy carbon electrode by cast-coating. The cyclic voltammograms of the GC/CMIm-PMo12 showed three well-defined pairs of redox peaks due to the PMo12 system. The GC/CMIm-PMo12 electrode showed great electrocatalytic activity towards the reduction of iodate. The analytical feature of the electrode for amperometric determination of iodate was evaluated.