Shown at John Carmack's keynote at QuakeCon, the presentation was a "pet project" that he had been working on for several weeks.
Running at 60 frames per second on iPhone 4, the engine also runs on 3G and 3GS with a framerate similar to Doom Classic.
Carmark described it as "incredibly cool" and said that it includes "all the mega-texture goodness" of the console and PC versions.
The engine will debut in a small-scale cheap application before the end of the year, with a more fully-fledged iPhone title to launch alongside Rage in 2011.
The presentation was the new project teased by Carmark earlier this week.
Doom 4 will not be present at the expo, and is scheduled for a 2011 reveal.