The automobile painting is a very energy and emission (solvents) intensive process step in the production of automobiles with regard to the small amount of paint applied to the car body. The awareness has risen that cleaner production technologies must substitute end-of-pipe control technologies. If these technologies strive for being a competitive option in corporate decision-making process, not only their environmental but also their technical and economical performance has to be on the same or better level compared to conventional technologies. The approach of Life-Cycle Engineering (LCE) by IKP and PE investigates technical, environmental and economical aspects of products and technologies to analyze weak points and optimization potentials as well as to support product and technology development. LCE methodology was applied to the comparison of 1K, 2K, waterborne and powder clear coat systems for automobile painting in a multi-client project.