Iran joined the Shanghai Cooperation Organization (SCO) as an observer member in 2005 and the year after applied for full membership. This application raised debates among SCO members, inside Iran and outside this organization in international politics. In the positive side, Iran's geostrategic importance and huge energy resources give impetus to SCO members. On the negative side, Iran’s challenge with the West, nuclear in particular, discourages SCO members to accept Iran at this juncture because they hesitate to pretend that they are standing against United States and the West. This article studies these debates in the theoretical framework of neo-realism and examines these events through historical analysis and according to their historical context. Considering the current international environment, membership of Iran in the SCO seems remote and very much depends, on the one hand on future progress of negotiations over Iran’s nuclear dossier, and on the other hand on relations between SCO members and the West.

Keywords: The Shanghai Cooperation Organization, Iran, Nuclear Dossier, Russia, China, Central Asian States, USA, the West