Rearrangements of oncogenes c-myc and c-abl were detected by non-radioactive hybridisation in a case of Burkitt's lymphoma/leukaemia. The surface phenotype of Burkitt's cells were positive for CD19, CD20, HLA-DR, CD14, CD33 and surface immunoglobulin markers. Although cytogenetic analysis was not performed, the c-myc and heavy immunoglobulin genes had the same 14.2 kilobase EcoRI molecular size fragment, suggesting a possible t(8;14) translocation which is a common marker of this malignancy. The c-abl oncogene was also rearranged in DNA digested BamHI and EcoRI. The physiopathological implications of the rearranged c-abl gene are unknown, this being the first case, as for as is known, of Burkitt's lymphoma/leukaemia with a rearranged c-abl gene.