A method is described to estimate MYCN (N-myc) oncogene amplification in neuroblastoma by the technique of differential polymerase chain reaction (PCR). The technique is quicker than conventional Southern blotting techniques and does not require radioactive materials. The ability to measure MYCN amplification from smaller amounts of tumor DNA also permits measurement from Tru-cut biopsy samples and opens the possibility of retrospective measurement of MYCN status from single paraffin sections of archival material.