The purpose of this research was to interpret the relationship between description and fantasy in a workshop on invention writing with sixth- and eleventh-grade students from two district educational institutions, whose theoretical foundation was argued from the postulates about description by Gloria Bernal, Rey, et al and J. Adams, in addition to the fantastic vision of David Roas, the proposal of writing as a socio-cultural practice by Delia Lerner, Anna Camps and Teresa Colomer, as well as, the pedagogical perspective of writing workshop supported by María Teresa Andruetto and Lilia Lardone. It is a commitment to qualitative research supported by the systematization of experiences suggested by Oscar Jara. For the application of the writing workshops, through which data was collected, 35 students from course 601 of Reino de Holanda School and 31 students from course 1101 of the Morning session of Germán Arciniegas School were convened. Based on the object of research and the specific objectives, the a priori categories were established: elements of fantasy, uses of description and fantastic descriptions. Among the most important results, we highlight the evidence that fantasy is not a privilege of children in initial education, but that young people in secondary and middle school also enjoy it, and at the same time extract from it, elements such as estrangement, uncertainty, transgression of the laws of nature, transmutation, which are recognized as transgressors of reality by linking them to the uses of description, which makes the production of fantastic descriptive texts possible.