The application of a production-oriented high-power CO2 laser system for the welding of auto underbody components is reported. Sheet metal sections, varying in thickness from 0.060-0.135 in, are welded at speeds up to 500 in/min at 6 kW. An overview of recent developments in laser welding is presented along with a discussion of the laser deep-penetration weld phenomenon. A comparison is made between laser and electron-beam welding performance.