The aim of this pictorial review is to introduce the radiologist to the differential diagnosis of a white hemithorax in children, to provide significant information on the diagnostic work-up, and to promote radiation-free techniques whenever possible. There are many causes of white hemithorax in children and it can be due to a variety of chest disorders. In most cases, plain chest radiographs and ultrasound will suffice. However, additional information provided by, e.g., CT or MRI is sometimes required.