Pulmonary nodules are commonly detected at computed tomography (CT) of the chest. More than 95% are < or = 10 mm; of these more than 95% are benign. Visual detection of pulmonary nodules by human readers is suboptimal, particularly with small nodules < or =10 mm. Computer-assisted detection can improve sensitivity and diagnostic confidence. Due to the high proportion of malignant lesions in nodules >10 mm immediate, often invasive workup is required including contrast-enhanced dynamic CT, positron emission tomography (PET) or biopsy. However, in nodules < or =10 mm the high proportion of benign lesions requires a non-invasive work-up usually based on follow-up with unenhanced CT. Invasive procedures are only required for growing nodules. Stable nodules require further follow-up and decreasing nodules are considered benign.