The existential psychoanalytic model addresses existential concerns and issues, particularly the existence/non-existence dichotomy with an emphasis on the issue of death.  The way of responding to these existential issues determines the actions, relationships, narratives, currents, and schemas of human life. Narratives, dramatic elements, and story patterns stem from existential concepts that can be examined within the framework of existential psychoanalytic reading. The play "Decline" suggests to be an existentialist drama throughout its narrative structure and story elements. This article attempts to analyze the relationships of the characters in the play, the plot, the events and main occurrences of the play, and the actions and reactions of the characters, with particular attention to existential philosophy, especially existential psychoanalytic theories and Irvin D. Yalom's existentialist approach. The main question here is how the fundamental existential conflicts and the issue of existence/non-existence as a metanarrative, main event, and reality in Akbar Radi’s "Decline"; influence the relationships between the characters, their acts and reacts, the conflict, the plot and other elements. Assumptively, existential manifestations and the way of reacting to existential issues and crises are the fundamental narrative in Akbar Radi's plays, as he is considered the father of modern Iranian playwriting. This narrative pattern can be traced in the story situations, dramatic settings, character relationships, actions and reactions of the dramatic society, and the main conflicts of the play "Decline". Therefore, this article, based on library resources, first discusses the function of existentialist topics and the principles and perspectives of existentialism in human relationships, actions, reactions, conflicts, and fundamental crises of human life. Then, it employs a descriptive-analytical method to interpret the existential reading of the play "Decline".