Tumor necrosis factor (TNF) receptor–associated periodic syndrome (TRAPS) is one of a recently defined class of autoinflammatory disorders called hereditary recurrent fevers. These disorders generally feature episodes of acute inflammation, fever, and pain. TRAPS was originally called familial Hibernian fever (FHF) to reflect the ancestry of the index patient, but has since been described in patients of various ethnicities. TRAPS is inherited in an autosomal dominant pattern and is caused by variants in the TNF receptor superfamily 1A (TNFRSF1A) gene. TNFRSF1A encodes a protein important to the inflammatory response. The pathogenesis of TRAPS is not entirely understood, but it has been found that variants in different locations of the TNFRSF1A gene lead to disruptions of the normal inflammatory response. Differential diagnosis of TRAPS is challenging as symptoms vary broadly and overlap with those of other disorders, and there is no functional test for the disorder. The key risk engendered by the long-term autoinflammation associated with TRAPS is amyloidosis, the potentially fatal accumulation of amyloid protein in organs and tissues. TRAPS responds well to corticosteroids, but as long-term use of these is undesirable, other treatments are being investigated, including the soluble p75 TNFR-Fc fusion protein etanercept.