An efficient, novel, and environmentally benign procedure for the thioacetalization of aliphatic and aromatic carbonyl compounds in the presence of catalytic amounts of tungstate sulfuric acid under solvent-free conditions to afford 1, 3-dithianes and 1, 3-dithiolanes was reported. This method has many advantages including excellent yields, short reaction time, and simple work-up procedure. Keywords: tungstate sulfuric acid; thioacetalization; 1, 3- ...