The incidence of secondary malignancies following chemotherapy is progressively increasing, mostly due to prolonged survival of patients treated for primary cancer. So far, only 3 cases of solid cancer following busulphan administration have been reported. We describe the case of a patient who developed a renal cancer after 4 years of busulphan treatment for chronic myeloid leukemia. Immunosuppression rather than mutagenesis seems to be responsible for the emergence of second solid cancers in patients receiving busulphan.