Hernia of Morgagni is the most rare of the four types of congenital diaphragmatic hernia (2 % - 3 % of all cases). In adults, it commonly presents with non-specific symptoms. In severe cases patients complain about shortness of breath and in lung function analysis a restrictive pattern can be observed. This paper presents a rare case of a massive diaphragmatic hernia of the right thorax which remained undiagnosed over many years and gives an up-to-date overview of the literature. The transabdominal approach using laparoscopic repair is favored in adults especially in non-acute cases. In our patient, the lung expanded postoperatively in most parts resulting in improvement of lung function and blood gas analysis.