The vessel, the Sparviero, toppled over yesterday as the crew were hauling in shellfish in rough conditions off the town of Civitanova in the Marche region.
The vessel sailed out of Puglia in southern Italy but had a mostly Romanian crew.
The bodies of two of the sailors, one Italian and one Romanian, were recovered and two other Romanians were unaccounted for today when rescue efforts were suspended because of the bad weather.
The boat has not been recovered.