The number of NHS outpatients who waited more than a year for treatment increased by more than 400% last year, according to new figures.
A total of 1,186 people waited more than 12 months for hospital treatment in 2016 compared to 228 in 2015, an increase of 420%, the Information Services Division Scotland data revealed.
The figures obtained by the Scottish Conservatives through Freedom of Information show of those waiting more than a year in 2016, 16 faced a two-year wait and two waited four years.
Most outpatients waiting more than 12 months were getting urology treatment (303), followed by people waiting for trauma and orthopaedic surgery (277) and gastroenterology patients (170).
The number of people treated in under a year fell by more than 28,000 in the same period from 1,462,989 in 2015 to 1,434,813 last year.
The party's health spokesman Miles Briggs said it was evidence of "shoddy planning" by the Scottish Government, adding "nobody should have to wait longer than a year for care".
He said: "This is just another measure which shows a real collapse in the standard of service being offered to patients.
"That's not the fault of hardworking staff - this is all on an SNP government whose shoddy forward planning has led to these unacceptable delays.
"To see these statistics shoot up by more than 400% in the space of just a year is remarkable."
Health Secretary Shona Robison said: "We remain committed to ensuring patients get quick access to the services they require.
"We announced an extra £10 million to deliver 40,000 more outpatient appointments immediately between November 2016 and March 2017, and have also provided an additional £50 million to improve waiting times at all stages of a patient's journey through the NHS.
"In December 2016, we published a new strategy for responding to the rising demand in outpatient appointments, aiming to free up 400,000 appointments.
"We have recently completed the consultation exercise and will be pushing ahead with this over the next year."
"To meet increasing demand, we are investing £200 million in a network of five new elective treatment centres across Scotland as well as expanding the Golden Jubilee National Hospital."