Abstract: The completion of the yeast genome project enables an analysis of various phenomena for a whole eukaryotic genome. We aimed at characterizing a full spectrum of target genes for a transcription activator, and specifically characterized putative targets for GCN4 in the budding yeast. The results suggest that about 1% of the genes are regulated by GCN4 and that these genes code for proteins involved in amino-acid and nucleotide metabolism. Our analysis proposes that, when enough data about the binding nature ofa transcription factor exists, it is possible to identify its putative targets and also to try and assign a physiological role for this transcription factor.