Work on the restoration of the Guildhall is set to commence this month, with Mayor Cllr Colum Eastwood saying the £3 million project will help to sustain the building for future generations.
The Guildhall will, he says, be the focus of the city's celebrations in 2013 when it assumes the mantle of UK City of Culture.
The project will see extensive external restoration work carried out the stonework, roof, windows and stained glass, with the clock also being restored. The work will also see the addition of new steps, and a ramp to the entrance off Guildhall Square.
Derry City Council says the Guildhall is an iconic building and the political hub of the city, and was the focus of global attention in June when the report of the Saville Inquiry into the events of Bloody Sunday was published.
The work is expected to cost in the region of £3m and continue until early 2012.
The building will remain open, but access may be restricted at certain times. The council is promising to keep inconvenience to the public to a minimum.