Police were called around 9.15am today and cordoned off a section of the road close to the Glasgow Dental Hospital.
Diversions have also been put in place.
A spokeswoman for Strathclyde Police said: "Sauchiehall Street has been closed at its junction with Holland Street due to reports of subsidence. Road closures are in place and drivers are being given alternative routes."
A spokesman for Glasgow City Council said: "Sauchiehall Street is closed at Elmbank Street and Elmbank Street is closed northbound at Bath Street. Road users are advised to avoid this area and seek an alternate route as delays should be expected."
It is the second time in just over a year that the road has been closed.
Last year Sauchiehall Street was closed for five months following a massive blaze.
Bus stops and a taxi rank were also relocated following the road closure.
The fire is thought to have started in the kitchen of Steak & Cherry.
Seventy firefighters battled it throughout the night, rescuing a family of five trapped in their top floor flat by smoke until finally extinguishing the blaze around dawn.
Restrictions were finally lifted and the raod reopened to traffic in July 2011.