Extraction and stripping of KAu(CN)(2) from alkaline solution by a w/o microemulsion formed with cetyltrimethylammonium bromide (CTAB) using Au-198(I) tracer has been investigated. Various parameters, such as the Au(I) concentration in aqueous phase, concentrations of halide ions, NH4SCN and thiodiethylene glycol in stripping solution as well as the relationship between water and Au(I) concentration in the organic phase in the extraction and stripping of Au(I) were studied. The results show that almost all of the Au(I) in the aqueous phase was extracted into the organic phase. The water content decreased significantly with an increase in Au(I) concentration in the organic phase, contrary to the results of a system with tributyl phosphate (TBP) as cosolvent. Almost all of the extracted Au(I) (similar to 98%) can be recovered with pure thiodiethylene glycol as the stripping agent, and similar to 93% of the Au(I) is stripped with high concentrations of NH4SCN(>3.0 mol dm(-3)) or KI (>2.0 mol dm(-3)).