Yemen underwent division and civil war unlike other nations in the Arab region. Yemen's division was the result of the world powers'trying to maintain supremacy during the imperialistic era. The clash between the two sides in the period of division was a proxy war of the two powers during the Cold War. Conflict over system and ideology was intense. Ideology conflict was fought between Islam and communism instead of between democracy and communism. As the world entered a transition period with the collapse of communist states of eastern Europe and the Soviet Union, the North and South Yemen were united again. Yemen was able to achieve unification with out interference of neighboring states or external influence. This was because the Yemeni ideology conflict was fought over Islam vs. communism not democracy vs. communism which does not involve interests of world powers. Nonetheless, imperfect unification of the country became a prelude to a civil war. The Yemeni civil war severely deteriorated causing numerous casualties and refugees. However, North Yemen was able to defeat South Yemen and achieve complete unification through superior military forces in the civil war. Also, North Yemen was able to remove their political rivals and threats in the South during the civil war providing a stable basis for united Yemen after the conflict. The unification of Yemen teaches several lessons to Korea. Problem of power distribution after unification, problems of incomplete military integration, economic difference, irrational community and problems of cultural integration are the problems that we should be on alert.