At the present time, there is no widely agreed definition of postprandial lipaemia (PPL). This lack of a shared definition limits the identification and treatment of patients with exaggerated PPL as well as the evaluation of potential therapeutic agents. PPL is a complex syndrome characterized by non-fasting hypertriglyceridaemia that is associated with an increased risk of vascular events. This review considers the definition of PPL and the methodology for assessing this process.