Some health boards have advertised jobs up to 24 times, the Liberal Democrats revealed after Freedom of Information request.
Half of available roles in Orkney are vacant, along with 35 per cent in Shetland and 37 per cent in the Western Isles.
BMA Scotland said the figures exposed “critical” vacancy rates in Scotland, and urged the future Scottish Government to set out a clear workforce plan.
One elderly care consultant vacancy in Dumfries and Galloway was advertised 24 times with no applicants, and a diabetes consultant role was advertised 23 times with just two applicants.
NHS Forth Valley reported a longstanding general psychiatry vacancy unfilled since November 2014 and advertised six times, while a radiology position in Fife has been empty for five years.
In total 102 vacancies have been unfilled for more than a year.
Liberal Democrat health spokesperson Alex Cole-Hamilton called the figures “worrying”.
“These figures show the stresses and strains that our NHS is operating under. This will be worrying for patients and mean extra work for existing staff,” he said.
"Staff are working around the clock but they aren’t getting anywhere close to the support and resources they need. The workforce is being stretched more thinly than ever, while dealing with more and more challenging workloads.”
Dr Graeme Eunson, chair of the BMA’s Scottish Consultants Committee, said: “We have been warning for some time that consultant vacancy rates in Scotland are at a critical level.
"The substantial long-term gaps in Scotland’s workforce are a growing and serious concern – stretching the workforce to the limit and affecting the ability of doctors to deliver the high-quality patient care they strive for.”
He added: “It is vital that this chronic shortage of doctors is addressed: we need to see serious steps in Scotland to make working as a doctor an appealing career choice, and show doctors they are valued.”
Speaking ahead of the Holyrood election, Mr Cole-Hamilton said: "Scotland desperately needs a comprehensive recovery plan which includes proposals for training and recruiting the staff that every health board is crying out for.”