By Miranda Eeles
BBC correspondent in Tehran
Prisoners from the 1980-88 Iran and Iraq war will return home after 15 years.
Thousands were taken captive during the war
The agreement to release them was reached last week following negotiations between the two sides.
The issue of prisoners of war has been a major obstacle to normalising relations between Tehran and Baghdad for years, with each country accusing the other of concealing how many prisoners it holds.
Under the agreement, 941 Iraqi prisoners of war being held in Iran and 349 Iranians will return to their respective countries.
It is expected that hundreds of relatives will go to the border post at Khosravi to welcome them home.
Both ministries have stated this is the final exchange to take place, although Iran has said the file of those missing in action would remain open.
Iraq has always denied the existence of Iranian prisoners of war, calling them common criminals instead.
Around a million people were killed in the war, with thousands of prisoners captured on both sides.
Over the years, with help from the International Committee of the Red Cross, many of these have been returned, including the remains of dead soldiers.
About one million people died in the eight-year war
The issue of PoWs is not the only reason why many in Iran feel bitter.
Thousands of people continue to suffer from the effects of chemical weapons used by Iraq during the conflict.
There is also a strong feeling in Iran that Iraq should pay compensation for the damage that it caused, estimated at billions of dollars.
Whilst this exchange reveals a desire to wrap up the human consequences of the war, the political relationship between Tehran and Baghdad remains extremely complex.
Both sides continue to harbour one another's active dissident groups.