The recently completed audit of Australia’s land and water resources has painted a rather grim picture of the state of our natural capital (NLWRA, 2001) and it is clear that some of our current land use practices are ecologically unsustainable. Many of our rivers and wetlands are in a degraded state and it is likely that without direct intervention and better management, their condition will continue to deteriorate. I have chosen the theme of my lecture this evening “Healthy river ecosystems: vision or reality?” to highlight some of these issues and consider what may be done to address them. I want to start by exploring what we mean by the term river health and, hopefully, provide a convincing explanation as to why the health of our rivers should be of great concern to us. I then will consider how we might go about making decisions as to what a healthy river looks like and what tools are available to us to measure ecosystem health. To conclude, I want to consider whether it is possible to sustain healthy river ecosystems (should we share this vision), given the kinds of things we do to rivers and their catchments. As I work through this, I wish to draw on some of the research undertaken in our Centre to highlight the important role that science, and aquatic ecology in particular, has played in informing this debate.