The purpose of this thesis is to examine the practice of yoga in Western actor training and theatre practice. The starting point of this PhD research is my observation that yoga is a popular discipline that has often attracted the interest of actors, directors, and actor trainers. The aim of this thesis is to explore through practical research additional possibilities for the use/application of the discipline in training and performance. More specifically, this thesis asks the following questions: " How yoga has been used by key theatre practitioners, such as Stanislavsky, Grotowski, Richard Schechner, and Dorinda Hulton, in their work with actors and how yoga has influenced their artistic vision? " How can I use the practice of yoga in order to facilitate the actor's training and rehearsal process in relation to specific dramaturgical and performative demands? " How do the social assumptions and historical contingencies that underlie the way yoga is practiced in the West today affect the actor's training, his/her relationship to one's body, and the way s/he embodies a role? The practical investigation employed the use of Iyengar Yoga in a series of three projects, which focused on performative and pre-performative aspects of the actor's craft. The practice of yoga postures was thus explored in relation to the actor's movement, imagination and performative relationship to other actors. It has also been used in order to facilitate the actor in working with different theatrical scripts and dramaturgies as well as generate original material for performance. In this manner, this thesis has developed a set of exercises and frameworks, which combine the practice of the discipline with its application in training and rehearsal contexts