Informal carers of people with Alzheimer's disease require access to high-quality information, which may be available through the Internet. Tools that have been developed to evaluate the contents of health-related web sites tend to be generic and not specific for diseases or patient groups. The aim of this study was to develop a tool that was specifically designed to evaluate web sites that provide information about Alzheimer's disease for informal carers of people with the disease. The tool was used to evaluate a sample of 15 web sites.