A global fundraising campaign has been announced by cathedral trustees, who have been forced to act as the building is suffering 'serious damage'.
The problem has been attributed to a combination of old age and modern pollution, but according to cathedral officials if action is not taken the 'rate of decay and damage-will increase dramatically - with potentially disastrous results'.
Urgent repairs are said to be required to avoid key areas of the cathedral being condemned as health-and-safety hazards.
In a statement, a spokesman for the cathedral said: 'Fabric conservation is the most urgent priority, with parts of the roof already leaking badly and elements of the masonry crumbling.
'Urgent work also needs to be carried out on the buttresses to the West Towers to avoid collapse, as well as the mammoth task of replacing the lead on the nave roof.'
The problem could easily spiral should cash not be secured. Canterbury Cathedral receives no state funding, and the prospect of fewer visitors would mean less donations.
Allen Willett, chairman of the Canterbury Cathedral Trust Fund, claimed the lack of financial backing since the war has had serious implications.
He said: '[The cathedral] is threatened by serious corrosion and deterioration caused by centuries of weathering and modern pollution, worsened by the limited repairs that scarce resources forced us to carry out following the war-time bombing.'
He added: '£50 million is a substantial sum, and it will need the generosity of the global community if we are to succeed - and succeed we must in order to protect Canterbury Cathedral for another 1,000 years.'