Excimer laser ablation is used as an effective surface cleaning technique for polyimide layers used in electronic packaging applications. Experiments are reported at 193 nm and 248 nm. At each of these wavelengths, ablations of the contaminated polyimide surface were carried out as a function of incident laser fluence. Quantitative determinations of contaminants present in the polyimide were made using surface analytical techniques. It is clearly demonstrated that excimer laser radiation at both 193 and 248 nm can be used to selectively remove trace metal contaminants from polyimide surfaces leaving intact the fine-line metallizations patterned on them. However, differences in the ablation thresholds, as well as in the ablation rates, are observed at these two wavelengths.