STORY: Around 36,000 people have been forced to leave their homes, and many of those who remained in flooded areas were left without electricity.
Agriculture has been hit hard in an area which grows fruit such as peaches, kiwis and apricots, as well as corn and grain.
The rain had stopped on Sunday and rescue teams and local volunteers were trying to pump water out of buildings and sweep away the mud-covered streets.
Authorities said flooding had hit 37 towns and communities and around 120 landslides had been registered. At least one bridge, near the city of Bologna, collapsed, some roads were undermined by floodwaters and many rail services were suspended.
The Italian government will hold a cabinet meeting on Tuesday (May 23) to decide on measures to help people to cope with the emergency.