Maintenance work totalling almost £860 million needs to be carried out on NHS buildings, a new report has revealed.
While the backlog for the NHS estate has fallen from more than £1 billion in 2011, the figures for 2013 revealed 10 hospitals in Scotland require £360 million of work to be carried out.
Aberdeen Royal Infirmary has the largest backlog, with £60.27 million of maintenance work required.
Taken together, it and the other nine hospitals - Ninewells Hospital in Dundee, Edinburgh's Western General, Dumfries and Galloway Hospital, Monklands Hospital, Crosshouse Hospital in Kilmarnock, Glasgow Royal Hospital, the Royal Edinburgh Hospital, the Victoria Hospital in Kirkcaldy and Glasgow's Southern General - account for 42% of NHS Scotland's £858 million maintenance backlog.
The latest report, examining the condition of the NHS estate, said that prioritising investment in these 10 hospitals "would make a significant contribution to reducing NHS Scotland's backlog maintenance burden".
NHS Scotland owns land and buildings worth an estimated £4.6 billion, but the report said the "outstanding backlog of £858 million remains a substantial issue to be addressed".
Despite "substantial capital investment over recent years" 28% of buildings are more than 50 years old, with a further 26% more than 30 years old.
While two thirds (68%) of the NHS estate was classed as being "functionally suitable" for its current use, the report said that 26% of buildings needed investment to improve their suitability, and 6% require either major investment or to be replaced to make them fit for purpose.
But a "significant amount" of the maintenance backlog is in buildings that health boards are planning to dispose of in the next 10 years, while about 21% of the backlog is in buildings not used for clinical work and will have "little impact on the patient's healthcare experience".
The report also highlighted the "ongoing challenge" the NHS faces in balancing investment between services and "that which is necessary to maintain buildings in a good condition and ensure that they are safe, reliable and fit for purpose".
In 2013-14 alone more than £525 million has been invested in NHS buildings and equipment,
The maintenance backlog, which fell by £90 million between 2012 and 2013, is also expected to decrease further. Health Secretary Alex Neil said a further reduction of £230 million was planned for over the next five years.
Health boards will target maintenance work on clinical areas, replacing old properties with modern accommodation, with plans to replace the Sick Kids Hospital in Edinburgh and Dumfries and Galloway Royal Infirmary, as well as the new £842 million South Glasgow Hospitals development.
Mr Neil said: "I want every patient in Scotland to be treated in facilities that are truly fit for purpose and as close to home as possible.
"That is why we are continuing to invest in buildings and equipment to enable our NHS to provide state-of-the-art facilities for patients and staff.
"The report shows that we are making significant progress in reducing the backlog of repairs needed and we will continue to build on this - planning for a further reduction of £230 million in five years.
"Patients and staff can be confident that this Government will do everything within our power to ensure that our NHS buildings are kept at the standards they deserve."