The Barthel Index is widely used in the evaluation of function. In Denmark at least three versions are used without a consensus of their specific formulation. The term ''Modified Barthel Index'' is used for several versions. A Barthel Index score without version has no meaning since a maximum score in one version indicates very poor function in another. This paper describes the proper usage of the Barthel Index and suggests the terminology ''Barthel-20'' and ''Barthel-100'' for the recommended versions published by Collin et al and Shah et al. The number after ''Barthel-'' indicates the maximum score.