Neuroblastoma, the most common extracranial solid tumour in children, is characterised by highly heterogeneous clinical behaviour; patients are stratified into risk categories according to a combination of clinical and biological markers. However, identifying non-invasive prognostic markers predicting outcome independently from current risk-stratification features remains critical for better disease monitoring. Using the SELDI-TOF-MS technology (surface-enhanced laser desorption/ionization time-of-flight mass spectrometry), we found a serum biomarker that strongly correlates with prognosis in neuroblastoma patients. Subsequent peptide mapping identified this biomarker as SAA protein. In support of this observation, high SAA levels were detected by ELISA in the sera of patients with poor prognosis neuroblastoma. Based on this finding, promises and limitations of the approach are discussed.