Troops formed an honour guard as the plane carrying the remains touched down at a US base in South Korea.
Relatives have waited years to retrieve the remains of their loved ones.
The repatriation was agreed at the June summit between US President Donald Trump and North Korea's Kim Jong-un.
The summit in Singapore, where the leaders agreed to work towards the "complete denuclearisation of the Korean Peninsula", has been criticised for a lack of details on when or how Pyongyang would renounce nuclear weapons.
More than 326,000 Americans fought alongside soldiers from South Korea and a UN coalition during the war to support the South against the Communist North.
Thousands of US military personnel from the Korean war remain unaccounted for and most of them - about 5,300 - were lost in what is now North Korea.