Focal pulmonary masses in children encompass a spectrum of conditions including congenital lesions, inflammatory masses, hematomas, and benign and malignant tumors. Congenital masses include bronchial atresia, sequestration, cystic adenomatoid malformation, and pulmonary vascular anomalies. Inflammatory masses most commonly result from infection and include pulmonary abscess, granulomas, and postinflammatory pseudotumors. Blunt trauma can cause a hematoma, which decreases in size on serial radiographs. Pulmonary neoplasms may be benign such as papilloma, hamartoma, and bronchial carcinoid tumor (low-grade malignancy), or they may be malignant as in sarcoma, carcinoma, and pulmonary blastoma. Because computed tomography (CT) is the most sensitive technique in detecting and helping characterize parenchymal disease, it has become the procedure of choice for further investigation of lesions seen or suggested on plain chest radiographs. Understanding the CT appearance of these lesions can allow an accurate diagnosis and optimize management of the patient's condition.