Morgagni-Larrey hernia is an exceedingly rare presentation of congenital diaphragmatic hernia. Despite its rarity, it is associated with significant risk of morbidity and mortality. Herein, we describe a unique case report of an elderly woman who presented with left-sided chest pain, dyspnea, and chronic history of recurrent respiratory tract infections. On the basis of her medical history, general physical examination and imaging studies, she was operated for a presumptive diagnosis of thymolipoma. However, the intra-operative findings revealed that it was an unusual variant of a diaphragmatic hernia and the hernia sac appeared through the retrosternal foramen of Morgagni. Hence we concluded that it was a Morgagni-Larrey hernia compressing the lungs and heart. Consequently, the hernia was reduced and the defect was repaired. During the postoperative period, the patient had an uneventful recovery. To conclude, the possibility of a Morgagni-Larrey hernia should be strongly considered while evaluating a patient with recurrent chest infections, dyspnea, and vague chest pain.