Fortilin is implicated in development, cellular processes and malignant transformation. However, a unifying picture of proteins in key processes pertaining to fortilin function is not yet emerging. To investigate the potential interactions, human fortilin was expressed in the yeast cells, and used to screen for fortilin binding proteins in a human skeletal muscle. Yeast cells were transformed in the sequential procedure using yeast two-hybrid expression vector (pAS2-1) containing full-length human fortilin as 'bait' for the first transformation, and pGAD10 vector containing a muscle cDNA library for the second transformation. In addition, a direct interaction of fortilin with known proteins, Ca²⁺ -ATPase, creatine kinase, glycogen phosphorylase, and troponin C was evaluated. ß-Galactosidase activity was assayed as an index of interaction between fortilin and the potential target proteins whereas yeast mating strategy was used to eliminate false positive and to reconfirm the actual binding. From this analysis, eukaryotic translation elongation factor-1 delta (guanine nucleotide exchange protein) was identified as a putative fortilin interacting protein.