"64 children have died at sea on the Eastern Med route to Greece since Jan 1," IOM wrote on its official Twitter account.
The Eastern Mediterranean migration route passes through Turkey, across the Bosphorous strait and the Aegean Sea into Greece.
Sea migration routes cause large numbers of deaths, with 70 percent of the world's migrant fatalities occurring in the Mediterranean in 2015, according to earlier IOM data, of which over one fifth occurred in the Eastern Mediterranean.
In 2015, 270 children died along the route, with 82 fatalities in December, 36 in November, 95 in October and 54 in September. No child fatalities were recorded by IOM prior to September.
Since late 2015, Europe has seen an unprecedented wave of migration, with thousands migrants from the Middle East and Africa arriving in the continent, mainly across the Mediterranean Sea.
Over 1.2 million irregular migrants have been detected crossing the EU border last year, according to the European external border protection agency Frontex. Over 840,000 refugees and migrants arrived in Greece via the Aegean Sea in 2015, according to the IOM.