Autologous stem cell transplantation is a therapeutic alternative for many chronic myeloid leukaemia (CML) patients ineligible for the only curative treatment of allogeneic bone marrow transplantation. In this study the retroviral transduction of CD34+ progenitor cells isolated from the bone marrow (BM) and peripheral blood (PB) of patients with CML was compared to that of CD34+ cells isolated from the BM and PB of normal individuals and patients with non-haematological malignancies. A highly significant increase in transduction of all cell types was achieved in the presence of the recombinant fibronectin fragment, CH-296 (P < 0.05). In the absence of fibronectin, centrifugation produced a marginal improvement in the transduction of all cell types, which was significant only for CMLBM progenitor cells (P < 0.05). There was no significant additive effect when centrifugation was included in the fibronectin infection protocol. In the presence of CH-296, combinations of three or more cytokines improved transduction for all cell types. The same degree of transduction was observed for both normal and CML cells, irrespective of the variations employed in the infection protocol, suggesting that both leukaemic and non-leukaemic progenitors are equally susceptible to retroviral infection. These results demonstrate that CH-296 has a universal beneficial effect on the transduction of haemopoietic progenitor cells, with clear potential for future clinical trials.