The use of pyridinium ionic liquids as solvent and catalytic systems based on yttrium salts dissolved in pyridinium ionic liquids for the synthetically important Diels-Alder reaction between cyclopentadiene and ethyl-vinyl ketone was studied. Both chloride and triflate were active catalysts in cycloaddition, strongly improving the reaction rate and stereoselectivity. The catalytic system-1 mol% YCl3/[C-4-3-C(1)py][OTf] (N-butyl-3-methylpyridinium trifluoromethanesulfonate) proved to be stable under recycling conditions.