Familial Mediterranean fever (FMF) is an autosomal recessive disorder characterized by fever and accompanying attacks of serositis. Cytokines such as IL-6, TNF-alpha, IL-1 beta are known to play an active role in FMF pathogenesis. Gilbert's syndrome, is a clinical condition that results indirect hyperbilirubinemia during febrile illness, surgery, vomiting and prolonged fasting period because of inhibition of UDP-glucuronide transferase activity. Increased bilirubin levels during FMF attack is caused suppression of UDP-glucuronide transferase activity by cytokines involved in the pathogenesis of FMF. Here, we report a patient who had serious indirect bilirubin elevation during an attack of FMF.