The use of effluent bioassays in various international jurisdictions is reviewed, resulting in an analysis of themes and trends in: regulatory use, different uses of bioassays in meeting protection goals, different types of bioassays, bioassay test variability, statistical design, use of effluent bioassays to predict receiving environment effects, and uptake of effluent bioassay testing by developing countries. Current effluent bioassay use by jurisdictions in North America, the European Union, and Asia/Pacific is described. The historical trend for many jurisdictions has been to start with chemical hazard-based systems, then add effluent bioassays (first lethal, then sublethal measures) and then use receiving environment evaluations to predict or measure impacts. For jurisdictions adopting effluent bioassays over the past decade, policies about the use of in vivo vertebrate tests appear to be influencing the types of bioassays that are used and there is also a trend towards micro-scale tests. In countries where regulations relating to effluent management do not require effluent bioassays, uptake of bioassays is relatively slow. Good practice for effluent bioassay applications can only be defined with regard to the regulatory regime, as differences between jurisdictions (e.g., hazard-based versus risk-based regimes, policies on in vivo vertebrate testing) will result in different choices.