Professor E. Gadd's Lab is a wooden shack inhabited by Professor E. Gadd in Luigi's Mansion and its Nintendo 3DS version. It also where he does research on the ghosts, particularly those at the location. Professor E. Gadd's Lab consists of a few rooms, with the main one being The Lab, as well as the Portrificationizer Chamber, Gallery, and the Training Room, all of which are larger than The Lab itself.
In Luigi's Mansion: Dark Moon, Professor E. Gadd's Lab is replaced with the Bunker, which particularly has the role of the The Lab room.