New figures also show more than £1m is being spent every year maintaining and securing empty buildings.
In total, there are 73 unused sites owned by the NHS in Scotland, with a total price tag of £66,594,309, or about £12 a head for every Scot.
Many of the properties have been empty for several years, with one having closed its doors more than 20 years ago.
Patients’ groups said the money could be used elsewhere in the NHS.
Margaret Watt, chairwoman of the Scotland Patients Association, said: “Anybody who has been holding on to property that long is crazy.
“To spend that amount of money on property that they are not even using is unacceptable. That is millions that could go back into the pot for new drugs that we don’t have in Scotland and other equipment.
“Anyone with a good business head would have put them up for lease. The money could be used for many, many things, such as more new beds for hospitals or for more staff, and for more training of staff.
“I think it’s crazy to sit there with all this revenue when we are so short-staffed and so short of doctors.”
TaxpayerScotland’s Eleanor McGrath said: “It’s deeply worrying that NHS Scotland has such a significant amount of unused property that is costing taxpayers so much.
“Taxpayers want to know that their money is being spent in the best way possible. They will be appalled at how seemingly relaxed these boards are acting about this unused property.”
Scottish Conservative health spokesman Jackson Carlaw said: “I can understand health boards perhaps wanting to hold on to properties until the market picks up.
“But some forward planning is also required and when new buildings are put up, plans should have long been in place to get rid of the old ones.”
NHS Tayside topped the list of health boards, with 11 properties worth £28m currently vacant. NHS Greater Glasgow and Clyde was second, with more than £17m worth, including Broomhill Hospital in Kirkintilloch, which closed in 1995 and is estimated to be valued at £4m.
Next was NHS Lothian with £15m of unused property.
Bangour Village Hospital in West Lothian is the country’s most expensive empty property, with a price tag of £8m. The former psychiatric hospital closed its doors in 2004.
NHS Forth Valley has six unused properties worth £3m, while NHS Lanarkshire is sitting on two empty properties, worth £1.25m. NHS Borders’ total was £310,000.