Round atelectasis is a benign inflammatory condition most frequently observed in patients with asbestos exposure but it can also result from a variety of chronic pleural diseases like infection. It has not previously been described in sarcoidosis. We report the occurrence of round atelectasis in four previously diagnosed sarcoidosis patients who were under follow up at our outpatient clinic. Three patients had symptoms consisting of thoracic pain, dry cough and sensation of fullness at the posterior thorax, respectively. Chest roentgenogram showed subpleural or pleural based opacity with diameters ranging from 2 to 3 cm in each of the patients. Chest computerized tomography (CT) revealed features of round atelectasis. Fiberoptic bronchoscopy with transbronchial lung biopsy was performed. Diagnosis was confirmed by the histopathologic examination of the biopsy samples. The mechanical influence of a prior pleural effusion due to sarcoidosis may be the predominant mechanism underlying the onset of round atelectasis in these patients. Clinicians should bear in mind the possibility of sarcoidosis as an etiologic factor for round atelectasis.