Key Clinical MessagesThe diagnosis of polyserositis due to tuberculosis (TB) is complex and challenging, which may cause delays in treatment. TB should be ruled out first before attributing polyserositis to any other cause like hypothyroidism, particularly in high TB burden countries.AbstractPolyserositis has numerous causes and frequently occurs in neoplasia, autoimmune disorders, endocrine conditions like hypothyroidism, and infectious diseases like tuberculosis (TB). The diagnosis of TB polyserositis is complex and challenging, which may cause the start of definitive therapy to be delayed. Here, we report the case of a 32‐year‐old female patient who presented with abdominal distension for 3 weeks associated with shortness of breath, cough, excessive fatigue, and loss of appetite. Thyroid function tests were suggestive of primary hypothyroidism, and later on, sputum GeneXpert MTB/RIF test turned out to be positive. She was initially started on oral levothyroxine and then anti‐TB medications. The polyserositis resolved a month after the initiation of anti‐TB drugs. TB should be ruled out first before attributing polyserositis to any other cause like hypothyroidism, particularly in high TB burden countries. Microbiologic tests, such as GeneXpert, remain the most important tools to make a diagnosis of TB and start anti‐TB medications early.