Yeast two-hybrid screening is a powerful method to identify proteins that interact with a protein of interest. CCN2 consists of four domains, and identification of new proteins that bind to individual domains of CCN2 may reveal a variety of CCN2 functions. To identify CCN2-interactive proteins that regulate CCN2 activity, we carried out GAL4-based yeast two-hybrid screening with a cDNA library derived from a chondrocytic cell line, HCS-2/8, with CCN2 cDNA used as a bait. In this chapter, we describe our methods for screening for CCN2 binding partners by this system in detail. This protocol may be applied to other CCN proteins as well.