Although the exact mechanism is not clearly understood yet, there were examples of the uptake of radiopharmaceuticals to the soft tissue lesions with $^{99m}Technetium$ methylene diphosphonate bone scan. Recently, we experienced two cases of neuroblastoma of which primary sites were imaged with $^{99m}Tc-MDP$ bone scan preoperatively and could make the diagnosis. So, we report here that $^{99m}Tc-MDP$ bone scan is the reasonable method not only to find out the bone metastasis, but also to diagnose the neuroblastoma preoperatively.