The threat to human health from climate change means that all levels of government and private and public agencies will need to change their current practices to reduce carbon emissions. The health sector will also need to respond and change practice. The National Health Service in the United Kingdom is developing a systematic and strategic approach to reduce its carbon footprint, as described in the recently released NHS Carbon Reduction Strategy for England. The work is being led by the Service's new Sustainable Development Unit. While the Australian health care system has not yet embraced a shared vision for carbon reduction, there are examples emerging of how the sector is contributing to reduce greenhouse gas production. Examples from two NSW area health services to reduce energy use and promote active transport are presented. In both countries, these changes are supported by new legislation and policy.