A lack of job opportunities in the rural north is being blamed for forcing graduates away from the region.
The claim follows figures suggesting most graduates from the University of the Highlands and Islands go elsewhere for work.
Lib Dem candidate Molly Nolan – who returned to the Highlands after studying at Harvard in the US – said she wants the next government to address the problem.
The SNP accepted there is still work to be done but said more people are choosing to stay and work locally.
Ms Nolan obtained figures showing 41% of UHI graduates find work in the region.
Of those who stayed in the Highlands, 67% got full-time posts, 25% got part-time work and around 3% started their own business.
The Caithness, Sutherland and Ross candidate said: “With more young people eager to stay in Highlands and Islands, it is deeply frustrating that so many graduates from our very own University leave in search of work elsewhere.
“While I don’t doubt some will choose to leave, all too often young people tell me there aren’t the opportunities to live and work in the communities they call home.
“With the added worry of rising youth unemployment, the next Scottish Government must urgently act. Ministers must plug this brain drain by prioritising affordable housing, digital connectivity and creating new green jobs.
“To deliver this ambitious plan for the future, we need to put the recovery first. By doing so, no longer will young people be forced to choose between career and their home.”
The figure was based on a sample of 1678 responses from graduates in 2017-18.
Lib Dems said the pandemic is also having an effect on younger people, with employment prospects being hurt further in rural areas.
SNP candidate for Skye, Lochaber & Badenoch, Kate Forbes, said: “More and more young people are now realising and taking advantage of the opportunities to enable them to live, study and work in the Highlands – however, there is still work to do to safeguard and value our rural communities, and make them sustainable and inclusive places for people to live, work and thrive.
“The SNP has already made it our national mission to create new, green jobs across Scotland – including rural areas and in land related industries, and our plans to tackle the population challenge in rural areas include action to encourage a more sustainable population pattern with fewer people concentrated around cities.
“We have already committed to a number of measures which will support young people to stay in the Highlands – including a new, £20 million Rural Entrepreneur Fund – providing grants of up to £10,000 to support the creation of 2,000 new businesses – delivering 100,000 affordable homes across Scotland, and even more investment in our digital infrastructure.
“The SNP is committed to supporting our young people to remain in and return to the Highlands – and ensure that the days of being forced away from your community because there are fewer prospects of studying and employment become a thing of the past.”