Selective electrocatalytic dehalogenation of 2,4-D in aqueous solution containing MeOH and tetraalkylammonium salt was directly performed under constant current electrolysis by using a membrane-separated flow-through cell with permeable cathodes made of palladium-loaded carbon materials. 2,4-D can be exhaustively dehalogenated to a chlorine-free product of phenoxyacetic acid at ambient temperature with 84-96% conversion at more than 80% selectivity.