This article examines the nature, uses, and limitations of the large variety of existing, so-called, hypnosis scales; that is, instruments that have been proposed for the assessment of hypnotic behavior. Although the major aim of most of the scales ostensively seems to be to assess several aspects of hypnotic states, they are found generally to say little about these and much more about responses to suggestions. The greatest application of these scales is to be found in research, but they also have a limited place in clinical work.