The theory of transformational learning, as originally developed by Jack Mezirow, is a cognitive process through which adult students find meaning in their learning experiences by transforming the initial perspectives that are problematic in a given situation into new, more inclusive perspectives which are better differentiated, more permeable, better integrated, and which will then guide their future actions. This article explores the constructivist foundations of this theory. Using a questionnaire, it also takes into account the transformational learning experience involved in the professional training of adult immigrants. Ideas for future investigations are also suggested.