&NA;Inborn errors of fatty acid oxidation (FAO) represent a group of metabolic disorders that has brought forward many interesting developments, as highlighted by the rapid pace of discovery of new defects and by the recognition of an ever‐increasing spectrum of clinical phenotypes. This review includes a clinical and biochemical summary of the FAO disorders known to date, a synopsis of four recently discovered defects (short‐chain 3‐hydroxy acyl‐CoA [coenzyme A] dehydrogenase deficiency, medium‐chain 3‐ketoacyl‐CoA thiolase deficiency, 3‐hydroxy‐3‐methylglutaryl‐CoA synthase deficiency, and long‐chain fatty acid transport deficiency) and of two susceptibility variations in the short‐chain acyl‐CoA dehydrogenase gene, and guidelines for the biochemical work‐up of candidate patients.