ABSTRACT/Insects are particularly suited for use in environmental impact assessment (e.i.a.) because of their high species diversity, ubiquitous occurrence, and importance in the functioning of natural ecosystems. Examples are given of the use of insects in the predictive phase of e.i.a., in the monitoring and assessment phase, and in the much rarer in* stance of an e.i.a, that includes both of these phases. The importance of working at the species level to understanding the results of e.i.a, is emphasized.