Hydatid cyst is a parasitic infestation caused by Echinococcus granulosus. Although liver is the most common site of infection, lungs may also be affected in 10 to 30 % of cases. The cyst is usually located in the lower lobes of the lungs. A 49-year-old male patient with a cavitary lesion in the posterior segment of the right upper lobe, was admitted to the tuberculosis ward with a preliminary diagnosis of lung tuberculosis (TB), and anti-TB treatment was started empirically. Bronchoscopy was performed after three different sputum examinations with negative results for acid-fast bacilli (AFB). Bronchoalveolar lavage examination was also negative for AFB. High resolution computed tomography showed findings of a ruptured hydatid cyst, rather than TB. A cysctotomy was performed to the patient whose indirect hemagglutination test result was negatıve for hydatid cyst.