Nearly two-thirds of England's Anglican cathedrals are worried about their finances, according to a survey for the BBC.
Thirty-eight of the country's 42 Church of England cathedrals responded. Of these, 26 said they were "worried" or "very worried" about the future.
The Church of England gave £8.3 million to cathedrals last year out of central funds, but the money goes nowhere near meeting all their needs.
Of England's 42 cathedrals, 38 are Grade 1 listed, most of them dating back to mediaeval times. Their staff includes not just clergy but also musicians, stonemasons and other building workers, with various kinds of support staff. The inevitable deterioration of ancient fabric requires constant effort to contain and fundraising is an essential part of cathedral administration. Daily running costs can be up to £4,000.
Gloucester Cathedral claims 70,000 people come to services each year and that there are 350,000 visitors, supported by 450 volunteers, 60 staff, and requiring annual expenditure of £2.2m.
Some cathedrals are able to capitalise on their location, with Southwark Cathedral in London running a conference centre described by the dean, Very Rev Andrew Nunn, as "essential".
"You have to be really imaginative and think what's going to be the most appropriate business model for my cathedral in this place at this time," he told the BBC.
"We're next to the Shard, very glittery, very glamorous, people want to access us for conferences. That wouldn't necessarily be the case in other parts of the country.
"Very few places have historic funds. People imagine we're sitting on large treasure chests from the past. That isn't the case."
Only eight cathedrals charge for entry, but the others ask for donations, which generate 20 per cent of their income overall.
The BBC quotes Very Rev Christopher Armstrong, dean of Blackburn Cathedral in Lancashire, who said he was "very worried" about the future.
"We're a northern cathedral, we're not on the tourist track, so we don't get any money from tourists.
"Like most cathedrals, we are in the red most of the time and if we are going to be sustainable we're going to have to change that."
However, the cathedral is about to enter a partnership with the local council which administrators hope will make it solvent again.
Cathedral attendance has seen long-term growth, bucking the trend for the Church of England generally.
Between 2003 and 2013, attendance at services held during the week doubled from 7,500 to 15,000 and even Sunday attendance rose slightly.
Overall the number of adults worshipping in cathedrals rose by nearly a third, from 23,100 adults in 2003 to 30,900 in 2013. Numbers of children also increased slightly overall, from 6,300 to 6,900.
On Sundays, adults attending services rose from 15,600 in 2003 to 15,900 in 2013.
The government injected £20 million into cathedrals starting in 2014 as part of its First World War Centenary Cathedral Repairs Fund. The largest single grant, £800,000 to Lichfield Cathedral, is credited with helping it stave off closure. However, as cathedrals also try to expand their ministry in the community, their need for funding is continually increasing.
