Background and Aim: Long-term respiratory, gastrointestinal, and vertebral sequelae are common after repair of congenital diaphragmatic defects (CDDs). The aim of this study was to assess the effect of these sequelae on the health-related quality of life (HRQoL) of adult survivors after CDD repair. Materials and Methods: A questionnaire, including 36-Item Health Survey Form (SF-36), 36-item Gastrointestinal Quality of Life Index (GIQLI), 55-item Psychosocial Survey, 9-item survey for Respiratory Symptoms-Related Quality of Life Index, and a symptoms query, was sent to 94 adult survivors of CDD and to 400 healthy control subjects. One SD lower than the age-adjusted national average in the 36-Item Health Survey Form score for physical or mental health was considered as low HRQoL. Results: Sixty-nine patients with CDD (72% ) and 162 (41% ) control subjects returned the questionnaire. The initial presentation was critical in less than 10% of patients with CDD. Forty-five patients with diaphragmatic hernia had primary closure; in 1 patient with diaphragmatic hernia, a patch was used. Twenty-four patients had plication of diaphragmatic eventration. The incidence of gastroesophageal reflux (20% vs 2% ), recurrent intestinal obstruction (7% vs 0% ), and recurrent abdominal pain (12% vs 2% ) was significantly higher in patients with CDD than in control subjects, whereas no difference in the incidence of respiratory, musculoskeletal, or other health problems not associated with CDD was found. Scores in GIQLI, Psychosocial Survey, and Respiratory Symptoms-Related Quality of Life Index did not differ between patients with CDD and control subjects. Health-related quality of life was low in 17 (25% ) of 69 patients with CDD, which exceeded 1.5 times the expected value. There was no correlation between the type or severity of the primary defect and HRQoL at the time of the study. Conclusion: Most adults with repaired CDD have good or satisfactory HRQoL. Congenital diaphragmatic defect-associated symptoms with or without acquired diseases significantly impair HRQoL in one fourth of the patients. Background and Aim: Long-term respiratory, gastrointestinal, and vertebral sequelae are common after repair of congenital diaphragmatic defects (CDDs). The aim of this study was to assess the effect of these sequelae on the health-related quality of life (HRQoL) of adult survivors after CDD repair. Materials and Methods: A questionnaire, 36-Item Health Survey Form (SF-36), 36-item Gastrointestinal Quality of Life Index (GIQLI), 55-item Psychosocial Survey, Respiratory Symptoms - Related Quality of Life Index, and a symptoms query, was sent to 94 adult survivors of CDD and to 400 healthy control subjects. One SD lower than the age-adjusted national average in the 36-Item Health Survey Form score for physical Results: Sixty-nine patients with CDD (72%) and 162 (41%) control subjects returned the questionnaire. The initial presentation was critical in less than 10% of patients with CDD. Forty- five patients with diap In a patient with diaphragmatic hernia, a patch was used. Twenty-four patients had plication of diaphragmatic eventration. The incidence of gastroesophageal reflux (20% vs 2%), recurrent intestinal obstruction (7% vs 0% ), and recurrent abdominal pain (12% vs 2%) was significantly higher in patients with CDD than in controlling subjects, an no difference in the incidence of respiratory, musculoskeletal, or other health problems not associated with CDD was found. Scores in GIQLI , Psychosocial Survey, and Respiratory Symptoms - Related Quality of Life Index did not differ between patients with CDD and control subjects. Health-related quality of life was low in 17 (25%) of 69 patients with CDD, which exceeded 1.5 expected value. There was no correlation between the type or severity of the primary defect and HRQoL at the time of the study. Conclusion: Most adults with repaired CDD have good or satisfactory HRQoL. Congenital diaphragmatic defect-associated symptoms with or without acquired diseases significantly impaired HRQoL in one fourth of the patients.