In this prospective study the efficacy of endoscopic sphincterotomy was evaluated in ten post-cholecystectomy patients with clinical and biliary manometric evidence of SO dysfunction. Ten patients (8 females, 2 males, median age 59 years) were assessed at a median period of 24 months (range 12-48) after endoscopic sphincterotomy. Eight of the ten patients (80%) were symptomatically improved after endoscopic sphincterotomy although only four were totally asymptomatic. The two patients who had unchanged symptoms after sphincterotomy have since had alternative diagnoses made and have improved on appropriate therapy. It is concluded that endoscopic sphincterotomy is effective in relieving symptoms in post-cholecystectomy patients with clinical and manometric evidence of SO dysfunction.