The authors describe a 6-year-old boy diagnosed with mediastinal Burkitt lymphoma with tumor invasion into bone marrow and both kidneys. After receiving chemotherapy according to NHL BFM-95 protocol for the high-risk disseminated lymphoma, the patient reached complete remission. He relapsed in the mediastinum at 5 months from the diagnosis. He underwent thoracotomy and tumor mass was removed by inferior lobectomy of right lung. Residual tumor progressed rapidly. Autologous stem cell transplantation could not be performed because of unresponsiveness to cytoreductive chemotherapy. Twenty-three days after the last chemotherapy course, he received rituximab at a dose of 375 mg/m(2) by intravenous infusion weekly, for a total of 8 dose. However, multiple intra-abdominal metastatic lesions were detected at the end of the therapy. Palliative radiotherapy was applied to these sites. He died because of disease progression, 11 months after the diagnosis.