Overweight and obesity are very common in Australian adults (56%) and children (27%). Rates of overweight and obesity are snowballing and will place greater burdens on health services for the treatment and care of chronic diseases. Prevention is urgently required from health, social and economic perspectives, but the response to date has been inadequate. A long-term, sustained action plan starting with a focus on young people is needed. This should particularly address the "obesogenic" environments causing the epidemic. Although whole-of-government action is required, support from and involvement by parents, carers, community leaders, healthcare professionals, teachers, childcare workers, urban planners, recreation managers, food manufacturers, employers, advertisers, and communicators is essential. The health sector should take the lead, but success will only come from concerted and integrated action across the whole of society. There are now signs of political commitment to addressing overweight and obesity. Doctors should get behind this and help mobilise community support.