A rare case of disseminated mucormycosis occurred in a 3-year-old boy suffering from a 4th degree neuroblastoma, treated with chemiotherapy and broad-spectrum antibiotics is reported. The child was admitted in the pediatric intensive care unit after surgical debridement of a wide part of the bowel showing necrosis and vessel thrombosis. After the histological diagnosis of mucormycosis in the gastrointestinal tract and the echographic detection of multiple mycotic localizations in the liver and kidneys, a treatment with high-dose amphotericin B was carried out. At the same time, the occurrence of anaerobiosis and/or acidosis as well as hyperglycemia was avoided in order to prevent the hyphae growth. This therapeutic strategy has been successful in preventing the infection spread, so that after 10 months from the discharge from the intensive care unit the child is in good health and the liver and kidney lesions are unchanged.