According to security sources cited by ANSA news agency, two people were found dead in the town of San Felice sul Panaro and another was killed in nearby Mirandola, where workers were trapped under rubble.
Several other people were also reported injured. The 5.8 magnitude tremor hit just nine days after a quake in the industrial northeast which killed six people and left thousands in makeshift tent dwellings with many homes and historic buildings reduced to rubble.
Today's quake struck 60 kilometres east of Parma, at a depth of 10 kilometres, according to the Geographical Institute of Modena.
The quake was felt throughout northern and central Italy, forcing the collapse of several structures already weakened by the 6.0 magnitude quake which hit on May 20.
In Pisa, home of the famous leaning tower, offices were evacuated as a precautionary measure. People ran out into the streets from shops and offices in Milan, Bologna and the Aosta Valley, close to the French border.
Around 7,000 people who fled their homes in the region when the first earthquake hit are still living in around 89 tent camps erected in fields, sports fields, car-parks and schools.
The camps can take up to 9,000 people. The region has been hit by a series of quakes and aftershocks over the past two weeks.