Nineteen children with neuroblastoma (aged 2 w.-7 y.o.) were studied to evaluate the optimal scan conditions for Iodine-123-Metaiodobenzylguanidine (MIBG) scintigraphy for accurate staging at the time of diagnosis. Six and 24 hours after an injection of 123I-MIBG, whole body image and truncal spot and SPECT images were obtained. Compared with other studies (CT or MRI and bone scintigraphy), each 123I-MIBG image was evaluated visually to investigate which image can demonstrate the extent of neuroblastoma most exactly. MIBG images demonstrated primary tumors in all patients, and metastatic lymphadenopathy in 8 of 9 patients. Twenty-four hour SPECT images gave us the most detailed information about the extent of abnormal accumulation. As to bone and bone marrow lesions, 6 hour images were superior to 24 hour images in detectability. Moreover, MIBG showed many more lesions and more extended accumulation than the bone scan. 123I-MIBG scintigraphy was very useful in detecting neuroblastomas. In order to get the most valuable information, both delayed SPECT and early whole body planar images should be obtained.