Objectives: To determine the incidence and outcomes of pneumothorax incritically ill patients admitted in intensive care unit (ICU). Study Design: Retrospective study.Setting: Intensive care unit of Nishtar Hospital Multan. Period: 1 July, 2016 to 31 Dec, 2016.Methods: Included analysis of 300 patients. Patients of all age groups and gender were includedin this analysis. We reviewed their clinical records regarding age, gender, incidence and type ofpneumothorax, pneumothorax episodes and its causes. Diagnosis of pneumothorax was basedon clinical examination and plain chest X-rays of patients. Results: Pneumothorax occurred onlyin 26 (8.7%) patients. Out of these 26 patients, there were 3 (1.0%) patients in whom spontaneouspneumothorax occurred and in remaining 23 (7.7%) patients pneumothorax was iatrogenic innature. There was significantly higher rate of mortality in patients who developed pneumothorax38.46%versus 3.2% in patients without pneumothorax (p-value <0.001). Duration of ICU staywas also significantly prolonged in pneumothorax patients 11.4 days versus only 6.2 daysin patients without pneumothorax (p-value <0.001). Patients with iatrogenic pneumothorax,mortality occurred in 5 (83.3%) patients in whom pneumothorax occurred due to mechanicalventilation, 1 (33.3%) in patients with central venous catheter insertion, 2 (22.3%) in patients withpericardiocentesis and 2 (40.0%) in patients with thoracentesis. Conclusion: Pneumothorax isassociated with a very high mortality and increased length of ICU stay. Mortality rate is higherin pneumothorax due to mechanical ventilation (barotrauma) as compared to other procedurerelated pneumothoraxes.