The clinical spectrum of childhood non-Hodgkin's lymphoma (NHL) is different from that in adults, with frequent extranodal involvement. CT scanning as part of routine staging appears to show more frequent sites of extranodal disease than were previously recognized. We have reviewed the CT and other radiological findings in 80 children with NHL to document the incidence and radiological appearance of visceral involvement, to compare this with the pattern of adult disease, and to assess how frequently clinical stage of disease was altered by radiological findings. The age of the children ranged from 9 months to 17 years 4 months (mean 9 years 2 months). The presenting site was in the abdomen in 21 (27%), extranodal sites in the head and neck in 18 (23%), mediastinum in 16 (20%), peripheral lymph nodes in 15 (19%), pelvic organs in four, skin in four, and bone in two. Fifteen children had gastrointestinal lymphoma, the majority involving the ileocaecal junction. The kidneys were involved in 10 children, the pancreas in three; no child with renal or pancreatic involvement had associated retroperitoneal lymph node enlargement. Eight children had bone involvement and only two of the 80 children had pulmonary nodules at presentation. In this series, of the 44 children who had CT of the chest and abdomen, only five had stage of disease increased as a result, three with the primary disease in peripheral lymph nodes, and two with the primary disease in extranodal sites in the head and neck.