Women and children left the M. Fiorillo ship first after medical staff conducted examinations on board.
The ship was carrying around 350 migrants who were rescued in the Mediterranean on Thursday.
The Mediterranean has become the world's most deadly barrier for migrants and refugees, with 3,500 thought to have died at sea last year and almost 2,000 so far this year. Many are fleeing poverty and violence in the Middle East and Africa.
In one incident Italy's coast guard rescued 1,800 migrants from seven overcrowded vessels just in one night.