Raw sewage and sewage at various stages of treatment were sampled from 15 municipal sewage treatment plants in south Queensland (Australia) and Canterbury (New Zealand). Estrogenic and androgenic activities were determined with sheep estrogen receptor and rainbow trout androgen receptor binding assays, respectively. Selected estrogenic chemicals were also analyzed by gas chromatography-mass spectrometry. The raw sewage influents contained significant levels of both estrogenic (<4-185 ng/L estradiol equivalents) and androgenic (1920-9330 ng/L testosterone equivalents) activity. Subsequent treatment of raw sewage successfully removed most of the activity so that the estrogenicity and androgenicity associated with the final effluents were very low (<1-4.2 ng/L estradiol equivalents and <6.5-736 ng/L testosterone equivalents, respectively). Secondary treatment was the most effective treatment step to remove estrogenic and androgenic activity from sewage water. Activated sludge treatment in particular removed 92% to >99% of the estrogenic activity and 82% to >99% of the androgenic activity in sewage.