Federation is a setup which has more than one level of governments. Bicameralism is the essential feature of federations. Bicameralism is most suited to the multi-ethnic states which have inherent potential to end up in chaos in absence of satisfactory division of powers. Bicameralism ensures continuity of legislation, second deliberation, impartial role in legislation and equal representation of all diverse federating units, balance of political power and accountability. Bicameralism is also best choice for transitioning democracies. In Pakistan, all constitutions after partition maintained uni-cameralism until separation of East Pakistan. Only after Dhaka debacle it was realized that domination of one federating unit, Punjab, and grievances of smaller ones should be patterned by some other way. It was realized in through bicameralism in the constitution of 1973. Senate is the upper body of parliament with equal representation from all federating units making sure that smaller provinces are characterized not by their numerical strength. Senate should guarantee impartiality and second deliberation to the matters considered at National Assembly overshadowed by majority population provinces. Provincial autonomy was the long demanded right of provinces which was brought about through 18th amendment to the Constitution. This amendment gave a new and dynamic role to the Senate. Multi-ethnic society like Pakistan needs equality at some elevated level where the small federating units can have feeling of equality and utmost power. This study is aimed at analyzing the role of Senate of Pakistan thoroughly and theoretically.