Myxedema coma is a rare, but potentially fatal condition due to severe hypothyroidism, and most commonly seen in patients with long standing, untreated hypothyroidism. Here, I report a case of a 75-year-old male who presented to the emergency department with acute respiratory failure and altered mental status. Interestingly, this case led to a new diagnosis of hypothyroidism presenting in its most severe form -myxedema coma. This case highlights the diagnostic challenges in identifying patients with myxedema coma and recognizing its potential role as a cause of respiratory failure.