Tuberculosis is a common etiological factor for fever of unknown origin in developing countries even today. Tuberculous mediastinal lymphadenitis is a disease of children as a part of primary tuberculosis. Mediastinal lymphadenitis without a parenchymal disease is unusual in an adult. Mediastinal tuberculous lymphadenitis presenting as fever of unknown origin could be mysterious when chest x ray was normal. Modern techniques like Computerised Tomography of chest and Endobronchial Ultrasound and Transbronchial Needle Aspiration (EBUS & TBNA) made it possible to make an early diagnosis in such clinical situations. We present a case of an adult with mediastinal tuberculous lymphadenitis with esophageal compression symptoms who presented with fever difficult to diagnose. And also we depict how modern techniques helped us to make an early and accurate diagnosis.