Built between 1841 and 1897, the Cathedral is the oldest surviving basilica in Ottawa, and is a prominent landmark in the city. The extensive interior and exterior restoration of the Cathedral included metalwork, stained glass, masonry, plaster, and artwork. Mechanical, electrical, and life safety systems were completely updated. The existing parish hall in the lower level of the Cathedral was also renovated.

Among other interior components restored to their original condition were the colour of the ceiling, 14,000 gold leaf stars, complex woodwork of the sanctuary, and approximately 150 wood and plaster sculptures by the renowned Québec sculptor, Philippe Hébert.

In December 1999, Edward J. Cuhaci and Associates Architects Inc. received the Order of Merit Award, the highest award from the Archdiocese of Ottawa, for exceptional services rendered during the restoration of the Cathedral. In May 2000, the roofing restoration work received the Annual Roofing Canada Award from the Canadian Roofing Contractors Association, for outstanding workmanship, innovative solution, and significant contribution to the community and industry. In December 2000, the Notre Dame Cathedral received an Award of Excellence - Heritage Conservation, from the Ottawa Architectural Conservation Advisory Committee. This award was "in recognition of the successful restoration of Notre Dame Cathedral, a project that contributes to the heritage character of Ottawa".