Function of CCN family proteins is determined by the interactions with multiple cofactors that are present in microenvironment. Therefore, finding out these cofactors is critically important in understanding the molecular function of the CCN family members. For this objective, bacteriophage random peptide display library is a quite feasible tool. In this library, each filamentous bacteriophage is designed to display an oligopeptide of random 12–16 amino acid residues on its surface. Bacteriophage clones that possess the peptides that bind to a CCN family protein are selected through several cycles of a process designated biopanning or affinity selection. By determining the nucleotide sequence of the DNA that encodes the displayed peptide, oligopeptides that specifically bind to the CCN family member can be specified. Obtained peptide sequences can be utilized for designing peptide aptamers for the CCN family protein, or as a key sequence to find out new CCN family cofactor candidates in silico.