Abstract: Electric guitars in present form are machined from solid blocks of various materials then coated with opaque paints that upon curing yield a guitar with a singular, permanent appearance. If the guitar were cast in a mold and transparent plastic resin used as a base material a multiplicity of appearances could be attained with one guitar. Internal illumination sources can be imbedded throughout the various layers of the guitar and when actuated by either the performer or a remote technician the appearance of the guitar can be changed during a performance. Illumination sources can change the color of the guitar by emitting different colors, imply motion by sequential flashing, create line sculptures, and relay video information to the performer.My invention, The Internally Illuminated Electric Guitar, makes the appearance of the guitar an internal property that is variable and controllable. In addition many manufacturing benefits are realized due to reduced manufacturing steps and reduced production time.