I-Share is a library catalog that provides information about the collections of many Illinois academic and research libraries. Participating libraries are collectively referred to as the I‑Share libraries. Currently, there are 65 I‑Share libraries and more than 30 million library items represented in the I‑Share catalog.

I-Share libraries make their collections available to individuals (such as students, faculty and staff) who have current valid affiliations with any I‑Share institution. Use your current ID from an I‑Share institution to request materials from any participating library, and these items will be sent to your library pickup location. Additionally, I‑Share libraries work with other libraries world-wide to share materials for library users. Please contact your institution's library for more information on these services if you do not find what you are looking for in the I‑Share catalog.

I-Share is one of several services of the Consortium of Academic and Research Libraries in Illinois (CARLI). CARLI was formed in 2005 from the consolidation of three library consortia including the former Illinois Library Computer Systems Organization (ILCSO). I‑Share was previously (1980-2005) known as ILLINET Online. I‑Share runs on computers hosted by the CARLI Office at the University of Illinois and uses Endeavor Information Systems' Voyager software.