The wooden boat which carried a total of 39 persons from Turkey's coasts to Greece sank after colliding with a Greek Coast Guard vessel amidst rough seas and strong winds.
Thirty-one persons were rescued during an operation by the Greek Coast Guard and Frontex forces.
Greek authorities later announced that the bodies of seven people were found. They include one man, two women and four children, among them a toddler.
The Greek Coast Guard said that the collision happened when a Turkish smuggler tried to escape by making dangerous maneuvers. It was still unclear whether he survived the accident.
The Greek Shipping ministry said during September, Greek authorities rescued 141,919 undocumented migrants and refugees in 795 incidents.
About 400,000 people have illegally entered Greece from the start of the year, fleeing war zones or aspiring for a better future in Europe.
More than 3,000 people have lost their lives this year in their attempt to reach Europe in similar sea tragedies across the Mediterranean.