DPP (IV) inhibitors have emerged as a new class of oral antidiabetic agents. These inhibitors promote glucose homeostasis by inhibiting degradation of glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) by DPP (IV). GLP-1 extends the action of insulin while suppressing the release of glucagon. Cayman’s DPP (IV) Inhibitor Screening Assay provides a convenient fluorescence-based method for screening DPP (IV) inhibitors in a 96-well format.