At least 74 migrants drowned off the Libyan coast, according to the UN.
The boat was carrying over 120 people, including women and children.
Forty-seven survivors were brought ashore by the Libyan Coast Guard and fishermen, 31 bodies were recovered.
The search for the victims continues, says the IOM.
The shipwreck, the IOM still says, occurred off the coast of Khums, Libya. "The loss of life in the Mediterranean is a manifestation of the inability of states to take decisive action to deploy a much needed search and rescue system in what is the deadliest route in the world," said Federico Soda. IOM Libya Head of Mission.