Genetic instability resulting from deficiency in replication error repair (RER) has been detected in a variety of human cancers. We have examined the stability of five 1p microsatellites in 51 human neuroblastomas including stages 1, 2, 3, 4 and 4s. None of the tumors showed an aberrant pattern indicating RER at any microsatellite. Our results do not support a major role for increased genetic instability as the result of deficient replication error repair in neuroblastoma.