After the Korean War, 333 South Korean people detained in North Korea as prisoners of war chose to stay in North Korea. During subsequent decades of the Cold War, some people of South Korean origin defected to North Korea as well. They include Roy Chung, a former U.S. Army soldier who defected to North Korea through East Germany in 1979. Aside from defection, North Korea has been accused of abduction in the disappearances of some South Koreans.
 Occasionally, North Koreans who have defected to South Korea have decided to return. Since South Korea does not permit its naturalized citizens to travel to the North, they have made their way back to their home country illegally, and thus became "double defectors". From a total of 25,000 North Korean defectors living in South Korea, about 800 are missing, some of whom may have returned to the North. The South Korean Ministry of Unification recognizes only 13 defections officially, as of 2014.
 Both sides have recognized the propaganda value of defectors, even immediately after the Division of Korea in 1945. Since then, the number of defectors has been used by both the North and the South (see North Korean defectors) to try to prove the superiority of their respective political systems (the country of destination).
 North Korean propaganda has targeted South Korean soldiers patrolling the Korean Demilitarized Zone (DMZ).
 A total of 357 prisoners of war detained in North Korea after the Korean War chose to stay in North Korea rather than be repatriated home to the South. These included 333 South Koreans, 23 Americans, and one Briton. Eight South Koreans and two of the Americans later changed their mind. However, the exact number of prisoners of war held by North Korea and China has been disputed since 1953, due to unaccounted South Korean soldiers. Several South Koreans defected to the North during the Cold War: In 1953, Kim Sung Bai, a captain in the South Korean air force, defected to North Korea with his F51 Mustang. In 1985, Ra il Ryong, a South Korean private, defected to North Korea and requested asylum. In 1988, a Korean employee at a U.S. army unit in South Korea defected to North Korea. His name was Son Chang-gu, a transport officer.
 During the Cold War, several U.S. Army servicemen defected to North Korea. One of them, Roy Chung, was born to South Korean immigrants. Unlike the others who defected across the DMZ, he defected by first crossing the border between West and East Germany in 1979. His parents accused North Korea of abducting him. The United States was not interested in investigating the case, as he was not a "security risk", and in similar cases it was usually impossible to prove that a kidnapping had occurred. There were several other cases of South Koreans mysteriously disappearing and moving to North Korea at that time, including the case of a geology teacher from Seoul who disappeared in April 1979 while he was having a holiday in Norway. Some South Koreans also accused North Korea of attempting to kidnap them while staying abroad. These alleged kidnapping attempts occurred mainly in Europe, Japan or Hong Kong.
 There are people who have defected from North Korea to South Korea, and then have defected back to North Korea again. In the first half of 2012 alone, there were 100 cases of "double defectors" like this. A possible reason includes widespread discrimination faced in South Korea. 7.2% of the North Korean defectors living in South Korea are unemployed, which is twice the national average. In 2013, there were 800 North Korean defectors unaccounted for out of 25,000 people. They might have gone to China or Southeast Asian countries on their way back to North Korea. South Korea's Unification Ministry officially recognizes only 13 cases of double defectors as of 2014.
 South Korea's laws do not allow naturalized North Koreans to return. North Korea has accused South Korea of abducting and forcibly interning those who want to and has demanded that they be allowed to leave.
 North Korea has targeted its own defectors with propaganda in attempts to lure them back as double defectors, but contemporary South Korean defectors born outside of North Korea are generally not welcome to defect to the North. In recent years there have been seven people who tried to leave South Korea, but they were detained for illegal entry in North Korea, and ultimately repatriated. As of 2019, there are reportedly 5461 former South Korean citizens living in North Korea.
 There has also been fatalities as a result of failed defections. One defector died in a failed murder-suicide attempt by her husband while in detention. One person who attempted to defect was shot and killed by South Korean military forces in September 2013.
 This is an incomplete list of notable cases of defections from South Korea to North Korea.