The evaluation and management of a patient with an SPN is guided by principles that were derived from earlier surgical studies. Stability or no growth for at least 2 years, the presence of calcium in characteristic patterns, and age less than 35 years without any associated risk factors are reliable indicators of a benign process. Fluoroscopy and localized tomography are helpful in evaluation of an SPN. If the nodule is still considered indeterminate, CT scanning, with the use of thin section cuts through the nodule, is now widely employed. If calcium is present in a characteristic pattern, the nodule is considered benign. If the nodule is very dense or more dense than a phantom reference nodule, the nodule has a high likelihood of being benign. Nodules that are less dense than the phantom nodule are indeterminate, and approximately 25% of these nodules will be benign. Computed tomography scan of the chest and upper abdomen is indicated in patients with a previous history of malignancy or when there is a high suspicion that the nodule is malignant. The further evaluation and management of SPNs that are indeterminate after CT examination are controversial. Some recommend tissue biopsy via transbronchoscopic or transthoracic approach, whereas others recommend immediate thoracotomy. Observation is indicated in certain situations when the chance of malignancy is quite low, the patient is not an operable candidate, or when the patient refuses further invasive evaluation. The physician's role in the management of a patient with an SPN is to educate and advise. The physician must be aware of the patient's anxieties, fears, and attitude and provide an opportunity for active participation by the patient in the decision-making process. Multiple pulmonary nodules are most commonly encountered in patients with metastatic disease to the lungs. Other less commonly encountered diseases that present as multiple pulmonary nodules include infections, arteriovenous malformations, Wegener's granulomatosis, and lymphoma. The evaluation and management of the patient with multiple pulmonary nodules are usually guided by the history, physical examination, and laboratory findings.