Klinefelter syndrome is one of the most frequent congenital chromosome disorders. Autoimmune diseases are not uncommon in patients with Klinefelter syndrome and associations between them have long been described. However, there is a paucity of literature regarding the effect of hypogonadism on respiratory system in these patients. Herein, we described a 28-year-old patient who presented with a constellation of unexplained respiratory signs and symptoms, such as tachypnea, hypoxemia, crackles recurrent pulmonary infections since childhood and progressive worsening of his pulmonary function, was diagnosed with Klinefelter syndrome in adulthood. CT chest with diffuse interstitial lung involvement and multiple cystic areas. Based on the radiological findings, an underlying autoimmune process was suspected and investigations showed findings compatible with Sjögren's syndrome. Double lung transplantation was thus indicated considering the irreversible interstitial changes in both lungs. Explant biopsy showed up histological pattern suggestive of interstitial lung disease with autoimmune features. Therefore, the importance of suspecting connective tissue diseases in patients with Klinefelter syndrome, perhaps due to the double X chromosome and a low androgen-toestrogen ratio that characterizes them.