This User Guide addresses disability data available in the 2000 Decennial Census. A decennial census of the United States is conducted every ten years to provide statistics at the national, state, and local levels. The short form of the decennial census collects basic demographic data from five out of six households, and the long form collects the same basic demographic data, plus social and economic data from the remaining one in six households. Data are also collected from group quarters (GQ), which include individuals living in institutions, a population that is rarely included in surveys. The primary purpose of the demographic data is to draw Congressional districts. The social and economic data from the long form is especially valuable because it provides social and economic statistics for small geographic areas (such as counties, towns, and Congressional districts) that are estimated in a uniform manner across the United States. The Census 2000 long form included six questions that are used to identify the population with disabilities. These data can be extremely useful to disability policymakers, disability service providers, and the disability advocacy community. This User Guide discusses the variety of information on disability, demographic characteristics, employment, and economic well-being available from Census 2000 long form data.