Between January 1970 and January 1990, 101 patients with paraesophageal hiatus hernias were operated on at the Lahey Clinic Medical Center. Thirteen patients had hernias that were identified as being iatrogenic in origin, a prevalence of 13%. Ten hernias were secondary to antireflux procedures, and esophagomyotomy, esophagogastrectomy, and placement of an Angelchik prosthesis accounted for one case each. Symptoms did not differ substantially from those of patients with primary hernias. Incarceration occurred in 2 patients, but neither sustained strangulation. The pathogenesis was most frequently disruption of a previous hiatal closure. Other etiological factors included disruption of the phrenoesophageal membrane by operative dissection, postoperative gastric dilatation, and failure to recognize esophageal shortening or an existing hiatal defect. Abdominal repair was usually possible, but 3 patients required thoracotomy for reduction. There has been one known recurrence during a median follow-up of 41 months.