First results of a prospective study about behavior evaluation of endoscopic sphincterotomy of the ampulla of Vater (EPE) through a serial surgical debitometric (RCDM) assessment are analyzed. Five patients submitted to an EPE looking for a biliary tract decompression because of clinical reasons, prior their surgical cholecystectomy, are comparatively evaluated by serial RCDM with regard to 24 patients receiving a broad transduodenal sphincteroplasty (EPTD). Normal debitometric values (N greater than or equal to 13 cc/min.) were obtained from a sample of 673 surgically explored patients. Debitometric behavior of EPE were comparable in all cases and over our standard (mean = 18.6 +/- 2.3 cc/min.); they showed no differences to surgical EPTD patients (x = 18.3 +/- 2.0 cc/min.). Despite uniform results in the EPE group, a more extensive sample is necessary for definitive conclusions; serial surgical RCDM in patients who received EPE, in spite of limited indications, seems to be a valuable method to analyze early functional events after the procedure.