Since global powers shape politics of the world for their self-interests and United States is the most influential power in the world today. Therefore, US foreign policy and its relations with other nations, especially with Pakistan in the South and west Asia is a prominent theme of international politics. So, this study helps us to understand the nature of US relationship with Pakistan i.e a cyclical pattern of cooperation and estrangement. This also enables us to understand the internal and external forces, which determine the cyclical pattern of relationship between the two countries during cold-war, post-cold-war and post 9/11, 2001 relations. It also sharpens insight regarding the transitional change in the relationship between Pakistan and US, i.e. Patron-Client relationship to Estranged-Client Relationship, due to transformation in international system. This dissertation also puts light on how such uneven interactions have affected the politics and security of Pakistan and expected future path of interaction. This also attempts to set forth a theoretical foundation that helps in understanding the identity (security related) construction that accompanies the Pakistan’s foreign policy collaboration with US. Major focus of the research is on the period of eight years i.e. 9/11, 2001 to 2008 that covers president Georg W. Bush junior’s administration in US and Gen. (Rtd) Musharraf’s regime in Pakistan.