The cathedral’s north transept is in need of urgent restoration because of the deterioration of the lead panels.
The Very Reverend Michael Tavinor, Dean of Hereford, said the lead had slipped, causing holes to open up in the roof.
The damage means that water has come into the building and started to stain the vault roof below.
The cathedral has been able to make temporary repairs but the lead panels will still have to be stripped off and replaced with new ones.
“We always knew that the roofs would be one of the next great projects,” said Mr Tavinor.
The cathedral has secured substantial grants covering the majority of the required funds.
These have come from the Wolfson Foundation, Pilgrim Trust, and the Mappa Mundi Trust.
However, the cathedral is looking to the public to help fill up the final £50,000 needed to meet the total repair costs.
“We hope as many as possible will help us,” said Mr Tavinor.
Anyone who donates £100 or more will be made patrons of the appeal and added to a special commemorative plaque.
To support the appeal visit www.herefordcathedral.org