[131I]Iodine-meta-iodobenzylguanidine ([131I]MIBG) is a radioactively labelled substance which is incorporated intracellularly by cells with neuroendocrine differentiation and used in the treatment of neuroendocrine malignancies. The agent was systemically administered on three occasions during a period of 16 weeks to a 4-year-old boy afflicted with disseminated neuroblastoma and suffering from severe pain caused by the disease. Initially, during the weeks immediately prior to radionuclide therapy, the boy required continuous intravenous infusions of morphine. On the 3rd day after each treatment, morphine administration could be discontinued and the boy appeared to be pain free. His appetite returned to normal and he became more mobile. The therapy had a good effect on his pain on each of the three occasions. Recurrent side effects were thrombocytopenia and cystitis. It is concluded that treatment with systemic radiotherapy in the form of [131I]MIBG was easy to perform and effective in this case of disseminated neuroblastoma and illustrates that this primary therapy can be used for palliative purposes.