The limited number of publications on repair of the foramen of Morgagni hernia concentrates mainly on the laparotomy approach. We present our experience with the transthoracic approach. Patients who were diagnosed as having a foramen of Morgagni hernia and were operated on via the transthoracic approach between December 1991 and June 2004 are reviewed retrospectively for their age, sex, presenting symptoms, and diagnostic and surgical procedures. Surgical repair was carried out via the transthoracic approach in all cases. Of the 24 patients who underwent transthoracic diaphragmatic repair of the defect, 16 were women and 8 were men, with an overall mean age of 55.1 years (range 42-69 years). In most cases the defect was on the right side; there was only one case of a left-sided defect. The most common presenting symptoms were dyspnea and gastrointestinal discomfort; five (20.8%) patients were asymptomatic. In 21 cases (87.5%) the diagnoses were established radiologically. The defect was accessed surgically via a posterolateral thoracotomy. No postoperative morbidity or mortality was observed. The mean follow-up was 8.3 years (14 months to 14 years), and no recurrence was noted. As important as the surgical repair of the foramen of Morgagni hernia itself is selection of the surgical approach so adhesions of the hernial sac from the surrounding tissues in the thoracic cavity are easily released. The transthoracic approach is amenable to safe primary repair of the defect and the release of adhesions, even in elderly and obese patients, in whom adhesions may be excessive.