The aim of the present study was to assess the utility of SPECT imaging with [123I]MIBG in patients with neuroblastoma (NB). Twenty-two children were studied (11 males and 11 females: age range: newborn to 11 years). A total of 39 studies were performed in different clinical phases. Both planar (at 24 and occasionally 48 hours) and SPECT (at 24 hours) imaging were performed in all cases. Planar studies gave a sensitivity of 87.5% (evidence of the disease in 21 of 24 studies performed in children with known NB lesions) and a specificity of 93.3% (true negative results in 14 of 15 studies performed in disease-free patients). In the same patients SPECT gave a sensitivity of 95.8% (23 of 24 positive studies and a specificity equal to that of planar scanning. In 5 of 21 studies positive at planar scanning SPECT showed 9 additional lesions. In conclusion, [123I]MIBG SPECT imaging compared to planar scanning can demonstrate a greater number of lesions. Its use seems to be indicated mainly in cases in which diagnostic assessment is difficult, such as small residual tumors or in the follow up of children no longer in therapy, in whom it can lead to an early diagnosis of relapse.