Dysfunction of the sphincter of Oddi (SOD) is an uncommon condition which must be considered in cases of persistent pain in the upper abdomen following uncomplicated cholecystectomy, when disease in other organs, such as gastric ulcer, esophagitis and pancreatitis has been eliminated. The pathogenesis is not fully elucidated, but it is assumed that the cholecystectomy in some cases induces an increased tendency to spasm in the sphincter of Oddi (SO), and, perhaps in connection with an increased sensitivity to pressure elevations in the biliary tree, results in attacks of pain. Whether fibrosis (stenosis) of the SO due to instrumentation or passage of stones is part of the etiology is obscure. Endoscopic retrograde cholangiopancreaticography with papillary manometry should be performed in all cases where SOD is suspected. An elevated basal pressure in SO seems to be the best indicator of SOD. In cases unresponsive to conservative treatment, endoscopic sphincterotomy may be considered. This treatment is not finally evaluated, but apparently the effect is good, especially in patients with elevated basal pressure in SO. It is emphasized that the knowledge of the behavior and regulation of SO is incomplete and that this should be remembered when criteria for SOD are applied.