Chest physicians frequently come across with the symptom hemoptysis, an alerting symptom which may result from a wide variety of disorders. In this study, we aimed to determine the main causes of hemoptysis in a reference hospital for chest diseases. All the patients who admitted to our emergency clinic with hemoptysis during three months of study period were included in the study. The mean age of 143 patients (106 males, 37 females) who were included in this study was 48 +/- 17 years. Medical history, physical examination and chest radiography were performed for each patient. Sputum examination for acid fast bacilli, computed tomography of thorax, fiberoptic bronchoscopy, ventilation-perfusion scintigraphy, echocardiography, ear-nose-throat examination and upper gastrointestinal system endoscopy were the further diagnostic investigations for selected patients. Bronchiectasis was the most common cause of hemoptysis (22.4%), followed by lung cancer (18.9%), active tuberculosis (11.2%), and inactive tuberculosis (10.5%). Sputum smear for acid fast bacilli was performed in 102 patients and were positive in 15.6% of them. Computed tomography of thorax was performed in 102 patients and was pathologic in 81.3% of them. Fiberoptic bronchoscopy was performed in 46 patients and localized the bleeding site in 67.4% of them. In conclusion, the most common causes of hemoptysis were bronchiectasis, lung cancer and tuberculosis in our hospital. Based on this finding, we suggest that, the diagnostic approach to the patients presenting with hemoptysis should include first a detailed medical history, physical examination, and chest radiography; second sputum smear for acid fast bacilli; third computed tomography of thorax and lastly fiberoptic bronchoscopy.