We report a robust method for studying en masse changes in translation using cDNA arrays. The relative distribution of messenger RNAs (mRNAs) along polysome gradients was monitored by performing cDNA array analysis of each gradient fraction and quantifying the mRNA translational status by regression analysis. Using this strategy to study human carcinoma cells exposed to short-wavelength ultraviolet light (UVC), we identified a subset of 17 translationally induced mRNAs and a subset of 69 translationally repressed mRNAs following UVC irradiation. We describe an effective approach for globally investigating changes in protein biosynthesis.