Commonwealth Catalog

commonwealth catalog - search for books, dvds, audiobooks, and more throughout the state

The Commonwealth Catalog (ComCat) allows library patrons to locate and request library materials from all across the state, and have them delivered directly to their home library. No need for mediated interlibrary loan. ComCat has a modern and easy-to-use interface, including book jacket images and improved search options. Users can easily select their preferred format for an item when multiple choices are available. Hardcover, paperback, large print, audiobooks, and DVDs will appear together in search results.

For promotional materials and graphics for online and print use, visit the ComCat toolkit page.

If your library is in one of these networks, your patrons can now use ComCat to request library materials beyond what's in your catalog.

Fenway Libraries Online (FLO)
Merrimack Valley Library Consortium (MVLC)
Metro Boston Library Network (MBLN)
Minuteman Library Network


Patrons may also explore ComCat as a guest.

ComCat Status

ComCat Online | 8 September 2017, 10:34 am
The Commonwealth Catalog is online. On September 10, 2017 CLAMS servers will go offline for approximately 5 hours while we perform an OS Upgrade. The maintenance window will begin at 7 A.M. and last for approximately 5 hours. We should be back on line by noon on September 10, 2017. On September 24, 2017 CLAMS servers will go offline for approximately 5 hours while we perform a Software Upgrade on our ILS. The maintenance window will begin at 5 P.M. and last for approximately 4 hours. We should be back on line by 9 P.M. on September 24, 2017. CLAMS users will not have access to Commonwealth Catalog during these upgrades.

Troubleshooting & Support

Library User?

Contact your library with troubleshooting or other questions about using the Commonwealth Catalog.

Participating Library?

Each library network has its own designated ComCat liaison. Contact your network headquarters.

Fenway Libraries Online (FLO) provides statewide support for libraries using the Commonwealth Catalog.

 Submit a helpdesk ticket