The translocation t(2;5), which leads to the fusion of the nucleophosmin gene (NPM) on chromosome 5q35 to the receptor kinase ALK on chromosome 2p23, is found in CD30⁺ anaplastic large cell lymphomas and some cases of B‐cell lymphoma. Hodgkin's disease (HD) is a malignant lymphoma characterized by large multinucleated tumour cells, Hodgkin and Reed‐Sternberg (H&RS) cells, surrounded by a dense lymphohistiocytic infiltrate. Our group recently demonstrated NPM/ALK fusion cDNAs by single‐cell RT‐PCR in < 3% of CD30⁺ tumour cells in 2/9 cases of HD. To further delineate the relevance of this finding for HD, we studied the occurrence of NPM/ALK fusion genes in peripheral blood cells of healthy donors by RT‐PCR. NPM/ALK fusion cDNAs were found by RT‐PCR in 14/29 healthy individuals and confirmed by hybridization with a breakpoint‐specific oligonucleotide. Due to the low rate of NPM/ALK‐positive cells in the peripheral blood of positive individuals, an assignment to a defined cellular subpopulation was not possible. We conclude that NPM/ALK fusion genes are present in peripheral blood cells of healthy donors. After t(14;18) and t(9;22), t(2;5) represents the third example of tumour‐associated translocation products in blood cells of apparently healthy donors. The implications of this finding are discussed.