Preliminary options for a new stretch of the A96 road between Forres and Fochabers run close to their retreat near Elgin.
Transport Scotland said it was at an early stage of assessing the route possibilities.
However the monks claim running close to the abbey would be a "catastrophe".
Brother Michael de Klerk told BBC Scotland of the possible route: "We couldn't quite believe it, it seemed extraordinary.
"If we are actually living by it, we would find it hard to absorb it, the noise would be day and night.
"The valley is quiet - you can hear a cow lowing. You would just hear a constant whirr of traffic."
Father Giles, who has been at the abbey for more than 40 years, said: "The are a lot of monasteries on the continent where they got railways running through and it has just destroyed the place.
"People come here for peace. Why destroy the peace here, it's just daft."
Transport Scotland said it would be two years before the final A96 corridor option in question was decided, and it would be engaging with local communities.
The aim is to improve journey times and road safety between Aberdeen and Inverness by 2030.
Monks at Pluscarden Abbey in Moray are warning their peaceful way of life will be threatened by a possible route for a new dual carriageway.