After the Cuban revolution, the U.S.-Cuba relations deteriorated, and eventually Cuba became an ally of the Soviet Union. In the decades that followed, the U.S. administrations utilized all kinds of diplomatic, economic and military means to overthrow the Castro regime. In 1962 Cuban missile crisis took place. The crisis contributed to the further antagonism between both sides. Since then the two countries have been in the enmity and separation. After severing ties for decades, Clinton administration intended to make changes in U.S.-Cuba relations, yet he was unable to make important progress under domestic dissension. The object of this thesis is to explore why Obama’s presidency could have achieved the re-establishment of U.S. and Cuba diplomatic relation successfully. Even though both U.S. and Cuba look forward to improve relations with each other, there are still differences and obstacles between them. The thesis also want to specify how they mended the lack of mutual trust through cooperation, and the agreements and consensus they had reached after opening negotiations on normalization of bilateral relations since December 17th, 2014. In this research, the author also investigates how the lifting of U.S.’s restrictions on travel and remittances influences Cuba politically, economically and culturally.