There are reasons why there are families separated between the South and the North and these reasons are linked to various events over different periods: the separation of people during the Japanese colonial era, the division in the peninsula, the establishment of two separate governments in the South and the North, the Korean war and people's fleeing and the continued Cold War after the ceasefire agreement. The hostile relationship and conflicts between the South and the North have been the common element in the separated family problem in the South and the North over the periods.

It was decided in the UN General Assembly on the 14th of November in 1947 that the South and the North would hold a general election. However, the Soviet Union opposed the decision. The South held its own general election and set up the government of the Republic of Korea on the 15th of August 1948. Subsequently, North Korea set up the government of the Democratic People's Republic of Korea on the 9th of September. As a result, the '38 postal exchange' program was completely discontinued on the 22nd of June in 1950.

During the process some people decided to defect to the South or the North due to conflicting ideological reasons. The following Korean War separated many families and some of them did not even know whether their family members were alive or dead. Since the Military Demarcation Line was set up in July 1953, the separated family issue has been going on until the present.