Human rights ombudsmen from more than 65 countries are meeting in Bolivia to discuss protection of migrants' rights.
Bolivia's president was himself a migrant worker
The UN wants to set up an international human rights network to monitor migrants and to reduce their abuse at the hands of people traffickers.
The meeting in Santa Cruz was attended by President Evo Morales, himself once a migrant worker.
He told the conference that migrants were demonised by rich countries like the United States.
At the age of six, President Morales worked with his family in the cane fields of Argentina, the BBC's Damian Kahya reports.
The UN is holding the conference in Bolivia because it is one of the countries most affected by migration.
It's estimated that about a quarter of Bolivians live abroad.
Many experience severe hardship and human rights abuses at the hands of traffickers.
Dyfan Jones, from the Bolivian Assembly of Human Rights, an NGO which works with returning migrants and their families, says the number of people leaving Bolivia is increasing daily.
"At the moment the estimate is of between 2m-3m Bolivians, and they face many problems.
"They're often abused and are forced to turn to prostitution and other unsavoury work in order to survive."