Background: Primary cricopharyngeal dysfunction (PCD) is a rare, idiopathic, functional disorder of the upper esophageal sphincter, characterized by dysphagia, frequent aspiration, and functional narrowing at the level of the upper esophageal sphincter. Methods: Five of 29 patients with oropharyngeal dysphagia were found to have PCD. Patients presented with severe dysphagia and predisposition to aspiration. Radiography demonstrated narrowing at the level of the upper esophageal sphincter and aspiration. An endoscope could be introduced into the esophagus in only 2 patients before dilation. Observations: In contrast to organic stenoses, these functional upper esophageal sphincter stenoses were dilated without difficulty with a balloon catheter. After low-pressure (1.5-2 atm) progressive balloon dilation (to 20 mm), superficial mucosal injury was observed only in one patient. After dilatation, symptoms resolved and barium swallow demonstrated normal passage through the upper esophageal sphincter. During a mean follow-up of 21 months (7-33), redilation was necessary in only 1 case. Conclusions: Balloon catheter dilatation of PCD is minimally invasive and provides both important diagnostic information and effective therapy. It should be the first choice of therapy for PCD.