Annotation files are for use by any interested party to understand what biological entities are represented on GeneChip™ brand arrays. Software developers who are interested in programmatic access and updates to NetAffx information should learn about the NetAffx SDK.


WinZip is required for accessing the files. Download and install a free evaluation version of WinZip. Then, download the zipped files to your hard drive using the links below and double click on the downloaded file to open WinZip and begin the installation.

For large files, we recommend that you first download a free download manager to expedite the process. The manager will allow you to speed up, schedule and pause/resume any downloads from the site. Download the free download manager prior to selecting your annotation file. Then, double click on the file you wish to access.


Annotation information is stored in a single file for each array type. This information is updated quarterly.

Catalog arrays

Exon arrays

Catalog arrays

Made-to-order array program