Thousands of cattle were culled in the 1990s to stop the spread of the brain-damaging and fatal disease.
The infrected cow was detected on a farm in Aberdeenshire, officials said.
Restrictions have been put in place at the unnamed farm as an investigation is carried out into the source of the disease.
Scotland’s Chief Veterinary Officer Sheila Voas said: “While it is too early to tell where the disease came from in this case, its detection is proof that our surveillance system is doing its job.
The animal did not enter the food chain, officials said.
