Those who live in the region were just starting to resume some semblance of normality in their lives when the quake struck about 25 miles northwest of Bologna at just after 9 a.m. local time.
Rescue workers combed through the rubble to search for victims. By late Tuesday, the death toll stood at 16, with one person missing, a worker at the machinery factory in the small town of San Felice Sul Panaro.
About 350 people were injured in the area known as one of Italy's more productive regions, agriculturally and industrially.
The quake was felt from Piedmont in northwestern Italy to Venice in the northeast and as far north as Austria. It was followed by many aftershocks, some registering more than 5.0 in magnitude.
The number of fatalities may go up as some are feared buried under the rubble of collapsed homes, churches and factories. A senior Italian official said at least seven people were missing and the number of homeless in the region swelled to 14,000.
The 6.0-magnitude temblor on May 20 was described by Italian emergency officials as the worst to hit the region since the 1300s. It killed seven people and damaged numerous buildings.
Italian Premier Mario Monti was meeting with emergency officials in Rome to discuss the impact of last week's quake when this one hit.
CORRECTION: Authorities first reported that the death toll was 17.
The Associated Press contributed to this report.