Febrile neutropenia and lung infections are common and potential fatal complications of pediatric cancer patients during chemotherapy. Lung ultrasound (LUS) has a good accurancy in the diagnosis of pneumonia in childhood. To our knowledge there are no studies concerning its utilization in the diagnosis and follow-up of pulmonary infection in children with cancer. The goal of this pilot study is to determine the accuracy of lung ultrasonography for the diagnosis and follow up of pneumonia in children and adolescents with cancer during fever. This is a prospective observational case-control monocentric study conducted in the Pediatric Hematology and Oncology Department of University Hospital of Catania in patients aged<18 years with cancer, with or without fever. Attending Physician used ultrasonography to diagnose pneumonia in children with cancer during fever. Non infected cancer patients were also tested with LUS to evaluate its accuracy. When performed, the results of chest X-ray and chest CT scan were compared with LUS results. Thirty-eight patients were studied. All underwent LUS, 16 underwent CXR, 3 chest CT. Statistical analysis showed LUS specificity of 95%, and sensitivity of 100%; CXR, instead showed a specificity of 80% and a sensitivity of 50%. The positive predictive value of LUS was 90% while that of CXR was 50%. The negative predictive value of LUS was 100% while that of CXR was 80%.This study shows for the first time that LUS allows physicians to diagnose pneumonia in children and young adults with cancer, with high specificity and sensitivity.