Neuroendocrine tumours often present a diagnostic and therapeutic challenge. They can arise almost anywhere in the body, and are therefore associated with a broad range of local symptoms. The systemic manifestations of neuroendocrine tumours are also diverse, and are related to the secretion of numerous hormones and biogenic amines. In recent years, improved diagnostic techniques, increased recognition of neuroendocrine tumour subtypes, and new therapeutic modalities have enhanced clinicians' ability to detect and appropriately treat these malignancies.