U.S.-Pakistan-China triangle depicts the interplay of complex power politics between regional and extra regional powers in South Asia. Pakistan and China have enjoyed a long and flourishing relationship for the last 6 decades whereas U.S.-Pak relations have gone through various ups and down. This analytical study focuses on U.S. Factor in Sino-Pak relationship while applying Neo-realist theory. A detailed analysis of 'Indian factor' in this triangle is also discussed keeping in view the improving Indo-China and Indo-U.S. relations. Pakistan has the most important Geo-Strategic location in South Asia and enjoys cordial relations with China despite being a major U.S. ally in War against Terrorism. In the emerging bipolar world, it will be imperative for Pakistan to gain maximum economic and political interests from both states in order to tackle Indian threat to its security and prosperity. This analysis will help the students and academia of Politics & International Relations to shed some light on this complex triangle and the power power politics in South Asia.