Background: Spontaneous non-traumatic pneumothorax is a relatively common clinical presentation in the Emergency Department. The diagnosis of spontaneous non-traumatic pneumothorax has evolved from basic chest radiography to the reference standard of CT imaging. Point-of-care ultrasound is another highly sensitive diagnostic modality that has gained increasing acceptance. Finally, the treatment of this type of pneumothorax has also been rapidly changing. Objective: We give an overview of the current literature regarding the definition and classification for pneumothorax. We discuss the current methods of diagnosis and management of spontaneous non-traumatic pneumothorax, which now include the promising treatment alternative of smaller pigtail thoracostomy catheters. We also discuss how a rapidly placed smaller pigtail catheter may be a viable single management option for a spontaneous tension pneumothorax. Discussion: The management of spontaneous non-traumatic pneumothorax has been rapidly advancing. Viable treatment options now include observation alone, needle aspiration and placement of a small pigtail thoracostomy catheter, in addition to the use of a traditional thoracostomy tube. Conclusion: Although the traditional treatment for a spontaneous non-traumatic pneumothorax was placement of a larger thoracostomy tube, this may no longer be the optimal management approach in these patients. The use of smaller pigtail thoracostomy catheters provides a viable treatment alternative to these larger catheters, and may also be used effectively as the only treatment step in a spontaneous tension pneumothorax. Placement of these smaller catheters sets the stage for potential outpatient management of pneumothorax, with increased comfort for the patient and possible cost savings.