A World War II bomb weighing 50 kilograms was found in the Fechenheim industrial area early Tuesday evening.
It is supposed to be defused in the night.
According to the police, the dud was discovered during demolition work on Carl-Benz-Strasse.
The forces cordoned off the site in a radius of 250 meters.
The Hanauer Landstraße was also affected, and there were traffic delays.
Since the area on Carl-Benz-Strasse is sparsely populated, only a few residents were affected.
The police spoke of a low double-digit range.
However, they had to leave their homes and apartments immediately.
The Frankfurt Transport Authority (VGF) has set up a support center.
Residents can stay at the McDonalds at Hanauer Landstrasse 334 in a specially provided bus while the defusing continues.
The Frankfurt fire brigade provides information via its Twitter account and refers to the website of the Federal Office for Civil Protection and Disaster Assistance.