Height adjustable desks with a keyboard tray system that is irradiated by an ultraviolet light disinfectant unit. The ultraviolet light unit resides parallel to and above the keyboard tray while being rigidly affixed to the underside of the desktop. The ultraviolet light unit also has the ability to irradiate the keyboard tray top when it is extended for typing and/or when it is retracted under the desktop for storage. And the ultraviolet light unit may be manually activated using a power switch located, for example, with the telescopic desk legs user control panel. And/or the ultraviolet light unit may be automatedly controlled, such as by being connected to a motion sensor to detect when a user is within close proximity to the keyboard, and thus turn off the UV light； and/or via a timer mechanism that activates the UV light unit for a regularly scheduled eradiation session.
