The extraction of 65Zn from falling liquid-metal drops of pure zinc and dilute zinc in lead alloys by fused-salt solutions of lead chloride and zinc chloride in the potassium chloride-lithium chloride eutectic has been investigated. Both chemical and isotopic exchange processes were found to be controlled by external mass transfer in the salt phase. The measured external resistances were comparable to those predicted by models based upon a rigid drop. Extraction in the pure zinc metal-lead chloride system appeared to proceed by a mechanism involving subchlorides as intermediates in the interfacial reaction.