The report said that some 385,000 Afghans have been repatriated from Iran, with just over half of them being forced to leave under deportation orders.
The IOM estimates that 1.5 million to 2 million undocumented Afghans are currently living in Iran.
The IOM also said that some 17,500 Afghans have returned from Pakistan since the start of the year. Pakistan hosts 1.3 million registered Afghan nationals, and more than 1 million Afghans who are unregistered, the IOM said.
High unemployment, a weak economy, and a precarious security situation in Afghanistan have driven the migration to neighboring countries and the rest of the world.