The German shell, which weighs up to 500Ibs, was discovered by construction staff in Aston on Monday morning, prompting a cordon which remained in place on Tuesday morning.
Residents told to leave their homes were offered sanctuary by the Parish of Aston and Nechells, and Aston-Newton Community Seventh Day Adventist Church in Lichfield Road.
Vicar, Rev Philip J Nott of Aston and Nechells parish tweeted: "Looking after people evacuated from WW2 bomb found in Aston. #allinadayswork".
Looking after people evacuated from WW2 bomb found in Aston. #allinadayswork @cofebirmingham pic.twitter.com/qUxYODgXUR
— Philip J Nott (@astonvicar) May 15, 2017
Homes and businesses within 500 metres of the unexploded device were evacuated. Police have warned the nearby A38 Aston Expressway will stay closed for most of Tuesday.
Birmingham Police Commander Chris Johnson, said: "An initial assessment from Army bomb disposal suggests this is a large explosive device and that's why an extensive cordon has been put in place for public safety.
"We don't take decisions like this lightly but public safety has to be our number one priority.
Some 80 people spent Monday night at a Red Cross rest centre.
Commander Johnson added: "Hundreds of homes have been evacuated and we are working with our partners to provide emergency accommodation.
"There have been some difficulties in accessing the device given the terrain and its position within a construction site but all agencies involved are working as quickly as possible to bring the situation to a safe conclusion with brave military staff risking their safety to ensure that of the public."