The building on the corner of busy London Road and Landressy Street in Bridgeton was evacuated in January and the main road has remained closed since.
Glasgow City Council will now pull down the building.
Owners of the flats, just yards from the Bridgeton Cross 'Umbrella', were served with a notice to either repair or demolish the building. That notice lapsed on April 27.
Building control officers have now assessed the building and have decided the only safe option is to demolish the block.
All the affected homeowners have been informed by letter and the demolition will begin within days.
It is hoped that this 200-yard stretch of London Road can reopen within weeks.
As reported in the Evening Times, the residents of the property were evacuated when subsidence was noticed in the property on January 13. These families have since been unable to return to their homes, other than to collect belongings.
Some residents also had their belongings stolen from the building after being evacuated.
Local businesses owners say trade has suffered due to the closure of the trunk route.
John Mason MSP, the SNP representative for Bridgeton, said: "At long last, we seem to have action and information coming from Glasgow City Council.
"I feel for the residents and business owners whose lives have been turned upside down since the start of the year. This has been going on far too long.
"The chaos caused to local transport and businesses by closing London Road for the last four months is very telling.
"This could, and should, have been handled better."
A spokeswoman from the council said: "The block on London Road and Landressy Street is in a very dangerous condition and continues to show concerning signs of movement and deterioration.
"While we are fully appreciative of the distress this decision may cause, we hope owners and tenants will understand that public safety is paramount and that the demolition of the entire block is now essential.
"We expect demolition will begin next week and the roads will remain closed until work is complete."
Local councillor George Redmond said: "This has caused much disruption in the Bridgeton area."
n Were you evacuated from your home on this block? If so, call Matty Sutton on 0141 302 6580.