INTRODUCTION: Pneumothorax is a serious medical condition, caused by the presence of air in the pleural cavity, which can lead to serious complications and even be fatal if not treated quickly. Chest radiography is the traditional diagnostic method, but it has limitations, and in this context, ultrasound has stood out as a promising alternative for the diagnosis of pneumothorax, having high sensitivity and specificity in some contexts. OBJECTIVES: This article aims to compare the diagnostic accuracy of ultrasound and chest radiography in the emergency department. METHODOLOGY: We carried out a broad search in several academic databases, using several Health Sciences Descriptors. The objective was to retrospectively compare the diagnostic accuracy of pneumothorax between radiography and ultrasound performed by non-radiologists in emergency patients. RESULTS: This study analyzed the effectiveness of chest radiography and ultrasound in diagnosing pneumothorax. 10 studies were included, 9 of which used the patient as the unit of analysis, with 1170 patients, and 460 with confirmed traumatic pneumothorax. 80% of studies presented a high risk of bias in patient selection. There was heterogeneity in the sensitivity of chest radiography, indicating the influence of the size of the pneumothorax, clinical conditions, and imaging techniques. Ultrasonography showed greater sensitivity and specificity than radiography; however, the results highlight the importance of considering different clinical contexts when choosing the best imaging modality to diagnose pneumothorax in emergencies. CONCLUSION: Thoracic ultrasound performed by non-radiologists is more accurate in diagnosing pneumothorax in emergency room trauma patients than chest radiography. The results highlight the potential of ultrasound as an effective diagnostic tool, easily integrating into trauma care protocols. Its use in medical training programs can improve the speed and accuracy of diagnosing critical conditions such as pneumothorax. The routine use of ultrasound in trauma management can bring positive changes to clinical practice, offering faster and safer interventions to patients.