The paper interrogates politics of rancor in Nigeria's fourth republic and its implication to ethnic divide, national unity and democratic development. Politics in Nigeria during post-independence and fourth republic is been played along ethnic, religious and regional linings and this has culminated to ethnic divide, national disunity and low political development. The distinctive code of conduct that depicts fairness and equity has eluded Nigerians thereby leading to behavioral derailment and attitudinal change in our political system and culture. Issues with regard to political appointments, promotions and heads of institutions are determined by ethnicity, religion and party affiliations thereby promoting political crisis and feelings of alienation. Political actors from various regions neither pursue issue of national interest rather active on politics of patronage and clientage. The paper adopts a qualitative method using secondary data and conflict of interest theory is used as a framework to the study. The paper revealed that the rationale behind politics of rancor is anchored on the notion that national leaders are recruited on the basis of their ethnicity, religion and region lining rather than their ability, experience, vision and national outlook in character. The paper recommends that Nigerians should do away with hate and bitter expressions which had for a long time undermine Nigeria quest to attain good governance and elect visionary leaders base on their abilities not ethnic and religious cleavages.