NHS Lothian paid out more than £2,000 for a specialist doctor to work an eight-hour shift.
The cash-strapped health board shelled out the cash for a gastroenterology consultant last year amid a recruitment crisis facing the NHS.
As of March this year NHS Lothian had 6.6 vacant consultant posts.
Spending on locum consultants across the whole of Scotland topped £100million last year.
Former SNP cabinet secretary Alex Neil said: “This is not good for patient safety. Nor is it a wise use of scarce resources.
“In these days of tight budgets, it is essential that we spend every penny of taxpayers’ money to maximum effect.
“on average locum doctors cost 80 per cent more to employ than permanent staff.”
A Scottish Government spokesman said: “Our NHS has been working to reduce both the use of locum doctors and their cost.
“NHS staff numbers are at a record high - and compared with 2011, there are now 1,628 more doctors, an increase of 15 per cent to 12,325.
“We’ve increased the number of funded medical school places this year by 50.”