The two incretin hormones, glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP), are secreted from the gastrointestinal tract in response to meals and contribute to the regulation of glucose homeostasis by increasing insulin secretion. Assessment of plasma concentrations of GLP-1 and GIP is often an important endpoint in both clinical and preclinical studies and, therefore, accurate measurement of these hormones is important. Here, we provide an overview of current approaches for the measurement of the incretin hormones, with particular focus on immunological methods.