Basal frequency of sphincter of Oddi phasic contractility has been repeatedly measured during endoscopic manometry and reported to range, in control subjects, from (M +/- SE) 3.0 +/- 0.6 to 7.5 +/- 0.7 c/min. Recently, high frequency (greater than 8 c/min) phasic contractions or absence of phasic activity were recorded in patients with postcholecystectomy or pancreatic complaints, possibly suggesting a sphincter of Oddi dysfunction. In the present study, sphincter of Oddi (biliary tract) phasic contractility was measured by perendoscopic manometry in 13 subjects without specific clinical symptoms of biliopancreatic disease and with a normal common bile and pancreatic duct at ERCP. Four T-tube patients with no evidence of common bile duct stones or papillary stenosis were studied for comparison (transductal sphincter of Oddi manometry). Basal frequency was found to range from 0 to 7 c/min (M +/- SE: 2.99 +/- 0.46) in perendoscopic manometry (85 min of recording time) and from 0 to 12 c/min (2.0 +/- 0.3) in transductal manometry (2546 min of recording time). Long lasting transductal recordings also showed that frequency of activity derived from the sphincter area varied cyclically in close relation with the duodenal migrating motor complex. It is concluded that the sphincter of Oddi in man is likely to participate in the interdigestive gastrointestinal motor activity and that short perendoscopic recordings may not be representative of the overall sphincter of Oddi activity.