The characteristic radiological findings which follow a Nissen fundoplication are reviewed. The esophagus may be narrowed but is intrinsically normal. A pseudotumor at the medial aspect of the fundus is generally present. The history and radiographic findings can normally differentiate this defect from neoplasm or a nonoperated hiatal hernia. Postoperative clinical evaluation has shown this procedure to be very valuable in the amelioration of symptoms.