The Thesis Seeks to understand the nature of Politics of Ethnicity and its relationship with national integration. In third world’s plural societies, ethnic politics has remained a great challenge. Pakistan is also a plural state having variety of ethnic groups. The ethnic heterogeneity has remained a constant challenge to the state authorities and the issue of nation building and creation of national integration is still a major task. It is seen in the research that the state of Pakistan always used centralizing and authoritarian policies to create national harmony. The state wanted to transform ethnic identity into Pakistani identity. The authoritative tactics of the state manifested ethnicity into ethnic politics. The dismemberment of East Pakistan in 1971, was the ultimate result. In the post 1971 period same policy was applied. Resultantly, ethnic groups from the four federating units, developed ethnic consciousness. In this research, three ethnic groups Baloch, Mohajir and Saraiki are selected to find out the main factors which politicized their ethnic association. The Researcher argued in this research that when state denies the demands of sharing political power or adequate representation in political and administrative institutions, conflictual situation develops between state and ethnic groups. It is also highlighted in detail that the political, economic and social factors determine the salience of politics of ethnicity. Apart from highlighting the factors responsible for politics of ethnicity and conflictual environment, the researcher also pointed out four variables to measure the threat for the national integration of Pakistan. These variables are the role of leadership of a particular ethnic group, the role of the middle class, their mobility for the particular cause, role of state and its policies in diffusing or escalating conflict and the role of external support for particular ethnic cause. The research also incorporated an extensive survey from the three ethnic groups of three provinces Balochistan, Sindh and Punjab. The research leads to a conclusion that some structural and perceptual perspective should be evolved to create national integration. For this purpose the role of state is very important. Instead of following the old repressive policies, political engagement, political reforms and social giving can bring about change in the plural societies like Pakistan.