Purpose: Etiological factors that cause iatrogenic pneumothorax were evaluated and the risk factors for iatrogenic pneumothorax in various diagnostic procedures and clinical applications were emphasized. Methods: From January 2003 to December 2004, we treated 196 patients with pneumothorax. Fifty-three of them were found to have iatrogenic pneumothorax. Patients' age, gender, primary diagnoses, etiology of iatrogenic pneumothorax, time of drainage and treatment results were analyzed. Results: Mean age of the 53 patients (26 women, 27 men) was 44.16 (range: 26 days-82 years). That was 27.04% of all pneumothorax patients. Mean time drainage was 8 days. Pleurodesis was applied to 6 patients with persistent air leak. Six patients (11.32%) died because of primary pathologies. No recurrence was seen in the other patients during the 2 to 6 months of the survey. Conclusion: With the increased number of thoracic procedures, the incidence of iatrogenic pneumothorax could be high in teaching hospitals. This depends on the experience of the doctor; therefore, we think that the procedures that may cause pneumothorax should be taught by experienced staff over longer periods.