The first cyclization/decarboxylation reaction of isatins with acyl chlorides promoted by 4-dimethylaminopyridine (DMAP) was described and a series of desired 3-alkenyl-oxindoles were obtained in good yields (up to 80%) and E/Z selectivities (up to 6.4/1). This protocol provided a new and feasible access to 3-alkenyl-oxindoles.