Abstract Summary: To facilitate the exploration of publicly available Zea mays expression data, we constructed a maize expression compendium, making use of an integration methodology and a consistent probe to gene mapping based on the 5b.60 sequence release of Z. mays. The compendium is made available through a web portal MAGIC that hosts a variety of analysis tools to easily browse and analyze the data. Our compendium is different from previous initiatives in combining expression values across different experiments by providing a consistent gene annotation across different platforms. Availability and implementation: http://bioinformatics.intec.ugent.be/magic/ Contact: [email protected] Supplementary information: Supplementary data are available at Bioinformatics online.