Summary. The present report analyses the distribution of 30-base pair (bp) latent membrane protein-1 (LMP-1) oncogene deletions in 24 cases of Epstein-Barr virus (EBV)-positive paediatric Hodgkin's disease (HD) and 39 normal controls.The 30 bp deletion was identified in 19/24 paediatric HD cases (79·2%), of which seven (29·2%) showed the deleted fragment alone, whereas in the remaining 12 (50%) it was accompanied by the nondeleted fragment. Conversely, the deletion was found in 8/22 (36·4%) EBV-positive healthy children, in two (9·1%) of whom the deleted fragment was alone, and was coinfecting with the nondeleted fragment in the other six (27·3%). The LMP-1 deletion was significantly associated with paediatric HD, both including dual infections (P ¼ 0·006) or excluding them (P ¼ 0·01).Type 2 EBV was carried by 25% of HD children, whereas all controls harboured type 1 EBV. The 30 bp deletion was present in all the paediatric HD specimens that contained type 2 EBV, suggesting that a deleted type 2 EBV strain may be more tumourigenic than a nondeleted type 2 EBV strain.These findings indicate that EBV strains carrying a 30 bp deletion in the third exon of the LMP-1 oncogene may have a more important role in the pathogenesis of paediatric HD than full-length EBV strains. Dual infection by LMP-1 deleted and nondeleted EBV strains is a frequent event both in healthy children and in the paediatric HD population.