Abstract: MOTIVATION: There is accumulating evidence that the chromatin environment of transcription factor (TF) binding sites in promoter regions has a critical influence on their regulatory potential. Recent studies have mapped TF binding sites and nucleosome positions throughout the yeast genome; however, there is a lack of computation tools to integrate these data types. RESULTS: We have developed the Ceres software to facilitate the integrated analysis of TF binding sites and nucleosome positions in the model eukaryote S. cerevisiae. Ceres enables users to dynamically display the spatial organization of TF binding sites and nucleosome positions of individual genes, or the average profiles for large gene sets. Ceres provides novel statistical tools to test for the enrichment of TF binding sites and chromatin environments for user-selected gene sets. Ceres also enables users to search the genome for combinations of TF binding sites that are associated with specific chromatin environments. Preliminary analysis using the Ceres software indicates that functional and conserved TF binding sites are often associated with specific chromatin environments. AVAILABILITY: http://bioinformatics1.smb.wsu.edu/Ceres CONTACT: jwyrick@wsu.edu SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.