The aim of this study was evaluation of the Id2 protein expression in neuroblastoma (NBL), including its influence on overall survival (OS) and disease free survival (DFS) as well as its correlation with known prognostic factors. The analysis of selected prognostic factors and their influence on OS and DFS was performed. In the years 1991-2005, among 100 patients treated for NBL 60 were evaluated. Id2 protein expression was examined by immunohistochemistry on paraffin embedded tumor tissue. All 60 analyzed tumors showed presence of Id2 protein expression. The evaluated tumors differed in the intensity of expression and the percentage of Id2 positive cells. The intensity of expression and percentage of cells had no influence on OS and DFS. There was no correlation with presence of other risk factors. In the whole group and in patients without MYCN amplification it can be supposed that there is a tendency to lower OS in patients with strong Id2 expression in NBL cells (p=0,07 and p=0,08, respectively). In the group without MYCN amplification there was a tendency to higher risk of disease relapse or progression in patients with stronger intensity of Id2 expression (p=0,05). The most important prognostic factors remained MYCN amplification and stage of disease. Although Id2 is not a prognostic factor in NBL, due to its abundant presence in NBL cells may be a potential therapeutic t ; arget.