OBJECTIVE Needle-knife sphincterotomy is an established technique in the management of some patients with biliary tract obstruction. However, the technique can be technically difficult in patients with very small papillae, specially when associated with distorted ampullary and duodenal anatomy. We present here a technique that may enhance successful needle-knife sphincterotomy in this situation. METHODS Eight patients with biliary tract obstruction who had small papillae and distorted ampullary or duodenal anatomy were evaluated. All patients had undergone one or more unsuccessful cannulations prior to referral. All eight patients underwent saline injection of their papillae, creating a bulging papilla, prior to needle-knife sphincterotomy. RESULTS Seven of the eight patients had successful needle-knife sphincterotomy following saline injection, and endoscopic therapy during the first attempt. In one patient, the procedure was successful at a second attempt 48 hours later. There were no instances of significant complications. CONCLUSIONS Saline injection into the papilla prior to needle-knife sphincterotomy may improve success rates in patients with unusually small papillae and distorted ampullary or duodenal anatomy. However, at present this technique should only be attempted by experienced endoscopists. Further studies with larger numbers of patients are required before the safety of this technique can be fully evaluated.