The invention relates to crystalline oxalate salts of biphenyl-2-ylcarbamic acid 1-(2-{[4-(4-{[(R)-2-hydroxy-2-(8-hydroxy-2-oxo-1,2-dihydroquinolin-5-yl)ethylamino]-methyl}phenylcarbamoyl)butyl]methylcarbamoyl}ethyl)piperidin-4-yl ester. This invention also relates to compositions containing such a crystalline oxalate salt; methods of using such a crystalline oxalate salt to, for example, treat a pulmonary disorder; and to processes for preparing such a crystalline oxalate salt.