The prognosis of pediatric neuroblastoma depends both on clinical presentation and on certain cellular and molecular characteristics. At the present time, two hypotheses can be drawn to explain both clinical and biological heterogeneity. In the first hypothesis, neuroblastoma progresses from early to late clinical stages through a classical multistep process linked to an accumulation of molecular abnormalities. In the second hypothesis, neuroblastoma represents an heterogeneous group of unrelated diseases, where most of stages I and II or stage IVS neuroblastomas can rather be considered as benign tumors, and stage IV neuroblastoma as a true malignant proliferation. To ascertain relevant biological factors for the prognosis of the disease, it is uppermost important that all investigators agree on biological criteria for analysis when neuroblastoma tissue is available in screened and unscreened populations. This paper reviews the biological tools available for prognosis in neuroblastoma, the priority for analysis of biological markers according to reliability, feasibility, and reproducibility of analysis procedure, and the conditions of tissue storage for further analysis of these biological markers. The standardized biological evaluation of neuroblastoma will allow, first, to collect sufficient data for multivariate analysis of prognostic factors and, second, to better define the putative links between various forms of the disease.