An in vitro recombinant yeast strain, transfected with the human androgen receptor was used to assess androgenic hormone disrupting potencies in leachates from Swedish landfills. It was shown that components in extracts of these affected the androgenic receptor and promoted a response in the beta-galactosidase marker system. Levels were within the range of those determined for domestic sewage effluents but lower than the highest levels found in an industrial effluent. These leachates finally enter receiving waters with or without wastewater treatment. Evidence was found for transformation during some of the wastewater treatments.