Recent work on the ecology and economics of biodiversity loss has indicated that the main ecpnpmic _costs _of species deletion to.the present generation are likely to be found ituhe lo,ss_pf resilience pf ecosystems providing basic life support services. This paper considers how ecological resilience relates to the sustainability of economic development. It is argued that maintenance of ecosystem stability is necessary to satisfy the basic criterion of sustainable economic development - that the value of the capital stock should be non-declining. Since ecological resilience is a measure of ecosystem stability, loss of resilience implies reduced ecosystem stability. Loss of resilience does not necessarily mean that economic development will be unsustainable, but itincreases_the.probability_that this mill be so. It also,increases.the burden on environmental management.