We present the case of a 71-year-old woman diagnosed with chronic lymphocytic leukemia who received multiple chemotherapeutic lines and evolved to acute lymphoblastic leukemia. The patient was Rai stage 0 at the time of the diagnosis and was monitored for almost 9 years. After that, the disease progressed and the patient began chemotherapy (fludarabine/cyclophosphamide combination), obtained complete remission and relapsed one year later after finishing treatment. She received multiple therapeutic regimens, accompanied by multiple infectious complications. After 8 years of evolution since she started chemotherapy, bone marrow aspirate and immunophenotyping revealed acute lymphoblastic leukemia. The occurrence of acute leukemia in CLL is rare and may arise from the same clone; however, most cases appear after patients have received chemotherapy, suggesting that they are therapy-related.