Background: Bleeding and trapped air in the pleural space are called hemothorax and pneumothorax, respectively. In cases where there are delays in diagnosis and treatment, the mortality rates due to hemopneumothorax can be significant. Hemopneumothorax is characterized by decreased lung sounds or chest percussion and subcutaneous emphysema. Diagnosis of pneumothorax and hemothorax can be achieved by portable chest X-ray (CXR), computed tomography (CT) scan, or ultrasonography. Portable CXR and CT-scans have their individual drawbacks. CXR creates a high percentage of false negative results, and a CT-scan is time consuming and less cost-effective; in addition, both modalities expose patients to radiation. Therefore, the introduction of ultrasonography as an easily available and highly accurate diagnostic modality has particular importance. Objectives: The aim of this study was to evaluate the sensitivity and specificity of ultrasonography in the diagnosis of pneumothorax and hemothorax in comparison with the other two methods, namely portable CXR and CT-scan. Patients and Methods: Patients (163) with multiple trauma who were suspected of having chest injuries, and who had indications for a chest CT-scan according to ATLS algorithms, were included in the study. All patients underwent portable CXR, CT-scan, and ultrasonography. Results: In total, 163 patients were included in this study; 29 patients had a pneumothorax, 24 patients had a hemothorax, and 23 patients had a hemopneumothorax confirmed. The study revealed that ultrasonography had a sensitivity of 96.15%, a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 98%, in the diagnosis of pneumothorax. The sensitivity for ultrasonography in the diagnosis of a hemothorax was 82.97%, with a specificity of 98.05%, a positive predictive value of 90%, and a negative predictive value of 92.66%. Portable CXR for pneumothorax detection had a sensitivity of 34.61%, a specificity of 97.95%, a positive predictive value of 90%, and a negative predictive value of 73.84%. In the detection of hemothorax, CXR had a sensitivity of 25.53%, a specificity of 95.14%, a positive predictive value of 70.58%, and a negative predictive value of 73.68%. Conclusions: Ultrasonography sensitivity and specificity for diagnosis of hemopneumothorax was high. The sensitivity of portable CXR was low despite its high specificity for the detection of hemothorax and pneumothorax.