The solitary pulmonary nodule is a common radiologic abnormality that is often detected incidentally. It is important to differentiate malignant nodules from benign nodules in the least invasive way and to make as specific and an accurate diagnosis as possible. In patients with a high probability of malignancy, surgery is the preferred strategy. Diagnostic algorithm for approaching the solitary pulmonary nodule, stratifying clinical risk factors in a standardized manner and blending this information with radiologic clues, would point the physician toward a benign or malignant cause. Such an approach would be expected to spare patients with benign causes the morbidity and cost associated with invasive tissue sampling and, at the same time, guide the physician toward recommending invasive tests for the nodules likely to be malignant.