Fludarabine phosphate (FDR) has demonstrated a remarkable clinical activity in chronic lymphocytic leukemia (CLL). Myelosuppression is the main toxicity although autoimmune hemolytic anemia (AIHA) is frequently reported. The pathogenesis of AIHA is still unknown however the role of T-cell immunosuppression is suspected. One case of thrombopenia after FDR has been described in a patient with a previous history of an autoimmune thrombocytopenia. We here report a 73-year-old man with a B-CLL and no previous autoimmune disorder who received six courses of fludarabine phosphate and developed afterwards an autoimmune thrombocytopenia.