From the Ballroom, doors lead into the Conservatory, which was used as an extension of the entertainment space. Erected in 1901-2, it was supplied by Mackenzie and Moncur of Edinburgh, on the recommendation of Young. Exotic plants and flowers were grown here, and have been re-introduced by the Office of Public Works. Hot water pipes that ran around the perimeter were covered up by cast iron grilles, which have been restored. The marble floor, which is original, is tiled in the traditional 18th century pattern of carreaux octagons.
This room posed one of the most difficult conservation problems for the OPW at Farmleigh, as it was in a dangerous condition when the State took over the house. It was completely re-glazed and new structural supports for high-level metal work were introduced. As a result the character of the Conservatory has been retained and its life span increased for at least another 100 years.