: Regioselective anodic monofluorination of aryl 2,2,2-trifluoroethyl sulfides gave, exclusively, aryl 1,2,2,2-tetrafluoroethyl sulfides, the products of fluorination at the position a to the trifluoromethyl group. The α-monofluorination of sulfides bearing electron-withdrawing substituents other than trifluoromethyl was also successful. Furthermore, the procedure could be applied to the α,α- difluorination of sulfides. The products are versatile building blocks and useful precursors of sulfur-free fluorinated compounds. © 1990, American Chemical Society. All rights reserved.