The prospects for the Trust's properties will be revealed on Friday
The National Trust for Scotland, (NTS), has announced that up to 90 jobs could be cut from its workforce, almost a fifth of its full time staff.
The organisation said the current economic climate meant it had to put "cost-saving measures" in place.
These include job losses across the organisation, "to secure the long term viability of the trust."
NTS, which is funded through charitable donations, employs nearly 500 full-time staff and 800 seasonal employees.
There will be a recruitment freeze on new seasonal staff.
The charity said it hoped to achieved as many job cuts as possible through voluntary redundancy.
A consultation period will begin next week.
NTS chief executive Kate Mavor said: "Like most organisations the trust has been considerably affected by the recession and we accept we have to respond to the economic conditions by making these cost savings.
"Inevitably, this includes reducing our staffing levels and doing everything we can to ensure the charity is more efficient if we are to have a sustainable future.
"Today's proposed job losses are very regrettable, but as staffing accounts for 50% of our operating expenditure, we must inevitably face the prospect of redundancies.
"Whilst we have taken some very difficult decisions, we are convinced that this is the right thing to do to secure the long term viability of the trust."
Established in 1931, NTS is the country's largest conservation charity.
It protects and promotes Scotland's natural and cultural heritage and owns or manages more than 130 countryside and built properties.
The charity has 320,000 members.
Details of how the the Trust's properties will be affected is expected to be announced on Friday.