Solitary pulmonary nodules are malignant in 50% of cases. The 5-year cure rate after resection of a malignant nodule averages 50% and is even higher if the nodule is small. Stability for 2 years suggests benignity, and the presence of calcification in certain patterns indicates that the nodule is probably benign. Biopsy of the nodule may establish benignity. The "wait and watch" strategy may be advisable under certain circumstances. Multiple pulmonary nodules are usually due to metastatic spread from an extrapulmonary primary tumor. Biopsy is usually advisable because the nodules may be due to a curable benign process.