When comparing clinical and tumour cytogenetic data on 14 neuroblastoma patients in different stages of disease we found a high incidence of 1p abnormalities (12/12), homogeneously staining regions/double minutes (9/12) and 2p abnormalities (4/12) in 12 unresectable and metastatic tumours (clinical stages III and IV). In contrast, these features were absent in clinical stage II tumours (2/2) with good prognosis. The coincidence of 1p aberrations with poor outcome of disease will be discussed.