More than 40 patients from the Royal Victoria Hospital are being relocated to Astley Ainslie Hospital after wards 3 and 4 flooded due to a burst water main on Sunday.
Firefighters were called to assist and extra staff were brough in to help with the removal of the frail older patients.
Melanie Johnson, nurse director at NHS Lothian, said: “It is understood a burst water main is the cause of severe flooding at the Royal Victoria Hospital.
“No patients were at risk, but as a precaution we have decided that it is in the best interest of the patients in wards 3 and 4 to move them elsewhere while we deal with the flood.
“We have contacted all families of patients in the affected wards to keep them fully informed of the situation.
“I would like to thank all of the staff involved, including our colleagues at the Scottish Ambulance Service and Scottish Fire and Rescue Service, who acted quickly to assess the problem and arranged for patients to be safely transported to the Astley Ainslie.”