This thesis discusses the scope for philosophy in and about film. It applies philosophical analysis to both the form and the content of Antonioni's films, and is thus both a philosophical approach to Antonioni's cinema as well as an exploration of his philosophical thought. The first part of the thesis reviews worthwhile discussions that are relevant to the complex relationship between film and philosophy. It also assesses the way in which the trend of philosophical thought known as existentialism fits into this relationship. General notions about existentialism are thus reviewed, as well as those that bear more particularly on art and cinema, and especially on the world as it is represented by Antonioni. Parallel to this, the thesis explores the role of time and space in film, and the philosophical implications of the way they are used by Antonioni. The second part of the thesis is devoted to the analysis of specific themes in Antonioni's films that relate them to an existentialist interpretation of reality. Chapter six is devoted to the early Antonioni, from his documentary shorts up to I1 grido, a period in which the phenomenological quality of his exploration of reality is already clearly noticeable. Chapter seven deals with Antonioni's peculiar narrative style and the way in which this style reflects his philosophical stances. The final chapters of the thesis are devoted to Antonioni's second important core of films and discuss the shift in Antonioni's central concerns. In films such as Deserto rosso, Blow Up, The Passenger, or Zabriskie Point, the connection with existentialism is related both to specific themes, such as anxiety and alienation, as well as to the more abstract philosophical stances that are implied by an existentialist worldview. In these films Antonioni questions reality itself, and discusses the limits of both our perception and representation of it.