Purpose Morgagni−Larrey congenital diaphragmatic hernia (MLH) is rare in adult patients and surgery is performed infrequently. The evidence regarding the most beneficial treatment modality is low. Nevertheless, with increasing experience in minimally-invasive surgery, the literature proves the laparoscopic approach as being safely feasible. However, knowledge on the disease as well as treatment options are based on single surgeon's experiences and small case series in the literature. Methods Retrospective single-center analysis on adult patients (≥ 18 years) with MLH from 01/2003 to 06/2019 regarding symptoms, hernia sac contents, surgical technique and perioperative outcome. Results 4.0% of diaphragmatic hernia repair procedures were performed for MLH (n = 11 patients). 27.3% of these patients were asymptomatic. Dyspnea or gastrointestinal symptoms were frequently observed (both in 45.5% of the patients). Colon transversum (63.6%), omentum majus (45.5%) and/or stomach (27.3%) were the most common hernia sac contents. Correct diagnosis was achieved preoperatively in 10/11 patients by cross-sectional imaging. All procedures were performed by trans-abdominal surgery (laparotomy in four and laparoscopy in seven patients). All hernias were reinforced by mesh after primary closure. No differences were observed in the perioperative outcome between patients who underwent hernia repair by laparotomy versus laparoscopy. Pleural complications requiring drainage were the most common postoperative complications. Conclusion MLH repair seems to be safely feasible by laparoscopic surgery. The benefit of mesh augmentation in MLH repair is not clear yet. In contrast to the current literature, all patients in this study received mesh augmentation after primary closure of the hernia. This should be evaluated in larger patient cohorts with long-term follow-up.