Allylthiourea was polymerized by constant current electroinitiation in acetonitrile using tetrabutylammonium fluoroborate as supporting electrolyte. The polymer obtained was insoluble in common organic solvents. FTIR studies showed that polymerization propagates by addition through the C=C double bond. The cyclic voltammogram of the monomer gave two irreversible oxidation peaks at + 1.3 V and + 2.4 V versus Ag-degree/Ag+ reference electrode at 25-degrees-C. Polymerization at room temperature gave a limiting conversion of about 10% for 2mA current and 30% for 5 mA current, in acetonitrile. Higher initial rates were obtained when dichloroethane was used as solvent.