Ultrasound examination of the thorax is an extremely valuable adjunct imaging modality in chest wall, pleural, mediastinal, and pulmonary disease. While air-filled lungs will obscure some deeper pulmonary lesions, ultrasound can evaluate peripheral pulmonary disease, mediastinal masses, and the extent and character of pleural effusions. Ultrasound guidance of needle biopsies and thoracocentesis provides safe and accurate lesion sampling.