We describe an 8-year-old hoy with chronic myeloid leukemia (CML), in lymphoid blast crisis at presentation. Ph chromosome was negative and he remained in complete continuous remission for 3 years. At 10 months from cessation of treatment he presented with involvement of both testcs. and bone marrow examination at that time was consistent with CML. Lymphoid blast crisis occurred again after 6 months. No further treatment was given, as parents refused permission.