A pulmonary nodule is a frequent and often incidental finding, and still represents a diagnostic challenge for radiologists. Although most solitary nodules are related to benign disease, some represent stage I lung cancers. and need to be distinguished from benign nodules in a cost-effective manner. The aim of diagnostic assessment should be to allow early treatment of small malignant nodules but avoid unnecessary biopsy or surgery, with their attendant risks, in patients with benign disease. The advent of Multislice Computed Tomography (MSCT) technology has sparked new interest in the non-invasive assessment of pulmonary nodules. Thanks to its ability to scan the whole thoracic volume with thinner collimations, this technology allows a more accurate identification and characterisation of pulmonary nodules, as well as the determination of perfusion patterns and growth rates. In this paper we present an algorithm for the diagnostic workup of incidentally detected small pulmonary nodules in subjects without known malignancy.