Xavier Dolan is often referred as ‘enfant terrible’ by the film critics. He is known for exploring mother/child relationship on screen through his cinematic texts including I killed my mother (2009), and Mommy (2014). The film, Mommy, won Cannes Jury Prize in 2014 and was appreciated globally. As suggested in the title, the film revolves around Diane or Die, mother of Steve, an adolescent boy who is suffering from ADHD. The audience has been told that Steve was young when his father died and since then he has been suffering from behavorial disorder. But as the film progresses, the relationship between Steve and his mother becomes intense. The audiences are left to wonder the cause of his anguish, his violence and his restlessness. Is it due to the absence of a father or his sudden death ? But, on the contrary, the film depicts the love of a child for his mother to the extent of maternal eroticism shared by both, Steve and Die. The central theme of the film is undoubtedely love. According to Julia Kristeva, a Bulgarian-French pschycoanalyst, primal repression (the seperation from mother) is essentiel for a child to form his identity. In this article, through a psychoanalytical approach, we will argue that Steve’s refusal to reject the ‘abject’ (the mother) becomes the cause of his anxious behavior and failure to develop his own identity.