Officers attended the scene to negotiate with the man before Sunderland RNLI were called at 1.03am after he fell into the River Wear.
With assistance from the Northumbria Police helicopter and Sunderland coastguard officers, the casualty was located and recovered onto a lifeboat.
Two RNLI volunteers then carried out CPR onboard the lifeboat and stabilised the man who was then taken to hospital.
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A Sunderland RNLI spokesperson said: “Thankfully on route to the marina the casualty’s condition stabilised ready for the transfer into the care of North East Ambulance Service NHS Foundation Trust paramedics.
“Following further treatment at the marina, the casualty was transferred to hospital.”
The force have since confirmed that the man remains in hospital where he is being treated for non-life threatening injuries.
A Northumbria Police spokesperson said: “Just before 1am we received a call reporting a man was on the wrong side of the railings of the Wearmouth Bridge.
"Officers attended the scene to negotiate with the man but he fell from the bridge and into the River Wear.
"He was recovered from the water by the Coastguard and taken to hospital by paramedics where he remains and is being treated for non-life threatening injuries.”
*Anyone who requires help and support in a time of need can call the Samaritans on 116 123.