2-(2,2-Dihalovinyl-3,3-dimethylcyclopropyl)ethanal is a new chemical compound and useful intermediate in the preparation of certain pyrethroid esters. It is prepared by hydrolysis of 2-[2-(2,2-dihalovinyl)-3,3-dimethylcyclopropyl]ethylidene diacetate, preferably in the presence of an acid.