Worldwide pressure on soil resources and the recognition by many international organizations, scientists, and universities of the importance of soils to humans and the natural world has recently led to further exploration of soils and their rarity. Looking to the U.S. Endangered Species Act as an example, we define a rare soil as one of limited areal extent and a threatened soil as one of greater areal extent undergoing a transformation that alters the soil's characteristics and function and makes it less able to carry out that characteristic or function (growing food, for instance). We propose a process to recognize rare and/or threatened soils based on five categories that could be used to describe the values associated with these soils: (1) economic value; (2) ecosystem value; (3) scientific value; (4) historic/cultural value; and (5) rarity. We propose not a legally binding designation, but a program modeled on several successful wildlife-oriented conservation awareness and education programs. We suggest that the most effective avenue would involve a cooperative effort similar to either Audubon's Important Bird Area program, The United Kindom's County Wildlife Sites, or Conservation International's hotspots designations. Under this process, anyone could nominate a soil-landscape continuum for status. We propose that the values categories suggested serve as a baseline for identifying soils that are most deserving of protection and public attention. Those who nominate a rare or threatened soil could state the case for its significance by describing its economic, ecological, scientific, historical/cultural, and/or rarity value. Nominations would be sent to a committee of soil scientists for review and acceptance or rejection. Accepted nominations would be mapped. We propose that the initial committee be an ad hoc committee under the leadership of the IUSS and consist of a broad array of members from the various fields of soil science and from various countries. Information collected via this nomination and mapping process would be centrally served to other organizations involved in conservation via the Internet and a Web server mapping site. This sharing of information would allow land use planners and conservation organizations to use the soils data as a consideration in their land use decision and designations of ecologically important areas. There is a basic lack of knowledge among the Earth's citizens and officials about the importance of soils in ecosystems and human life, and by providing scientifically valid designations of rare and threatened soils, other conservation organizations could reliably incorporate this information into their designations. The International Union of Soil Sciences brings to the conservation table a unique depth of knowledge about soils that is lacking in many other organizations, and through this designation process, we could help close that knowledge gap.