CorsixTH is an open-source re-implementation of Theme Hospital, explicitly designed to use the original game's visual and audio assets, but adding a modern UI and what would now be considered standard graphical options, including support for higher resolutions and greater color depth. The source code and binaries are licensed under a freeware license. As of version 0.50, Windows XP is no longer supported, and the Visual Studio 2013 Redistributable is now required for the program to run. Additionally, the level editor, due to technical problems, is not included in 0.5.0.

The original game files are required, and the software is incapable of operating without them; the original CD-ROM is required, or a copy of the game files from a digital version, such as the version that can be purchased legally through either Steam or The re-implementation is incomplete, and is currently in Alpha status.