The purpose with this work is to describe the language that is built around the chronic fatigue syndrome (CFS) in Sweden. Our questions are: What does the professional field look like; who writes, about what and for which kind of readers? How do they describe the expressions and the upcoming of CFS? For which reasons can CFS be considered as a medical diagnosis/illness? How can CFS be understood from a social perspective? Our theoretical starting point is a social constructive theory and also Karin Johannisson's theory about medicalization and Foucault?s theory about power. We have from a literature-exposition of Swedish articles from 1989 to 2006, done a social constructive discourse analysis with help from Laclau & Mouffe's discourse theory, and Fairclough's model of social practices. In our textual analysis we found three dominating discourses: A medical discourse, a social/cultural discourse and a general/popular discourse.