Thirty-five children (aged 0-9 yr) who had presented with Stage IV neuroblastoma were studied to see if avidity for 67Ga or 99mTc-methylene diphosphonate (MDP) uptake in both primary and secondary sites at diagnosis conferred any prognostic significance. Twenty-three percent of the patients were disease free and off treatment at the time of study. Crude survival did not differ between groups. Duration of survival and the likelihood of completing treatment were related to the scintigraphic appearance at the time of diagnosis, after adjustment for potential confounding effects, using Cox's proportional hazards regression and multiple logistic regression. After adjustment for confounding influences, neither 67Ga avidity nor uptake of 99mTc-MDP was associated with a significantly worse prognosis, both in terms of adjusted survival and likelihood of completing treatment. Patients with 67Ga-avid scans at diagnosis did not demonstrate significantly worse survival (HR 1.47, 95% CI 0.43-5.11) than those without 67Ga avidity. They were somewhat less likely to complete treatment (OR 0.23, 95% CI 0.03-1.63), but this did not reach statistical significance. Similarly, although patients with 99mTc-MDP positive scans demonstrated somewhat worse survival (HR 2.47, 95% CI 0.45-13.54), this result did not reach statistical significance, nor were they less likely to complete treatment (OR 0.69, 95% CI 0.07-6.67) than those with 99mTc-MDP negative scans. Uptake of 99mTc-MDP into extraosseous sites was also not associated with worse survival (HR 1.45, 95% CI 0.58-3.62) nor with decreased likelihood of completing treatment (OR 0.78, 95% CI 0.12-5.09). Other than indicating disease stage, these results do not support the hypothesis that the scintigraphic appearance at diagnosis confers prognostic information in children with advanced neuroblastoma.