Prolymphocytic leukemia (PLL) is a malignant lymphoproliferative disorder, characterized by massive splenomegaly, predominance of prolymphocytes in the peripheral blood and bone marrow, minimal lymph nodes enlargement and poor prognosis. It accounts for a 5-10% case of chronic lymphocytic leukemia (CLL). Patients age is usually over the fifth decade, the disease is 4.1 more common in males. More than 80% are B-lymphocytic derived cells showing a post-thymic phenotype. Median survival of B-PLL patients is 3 years, while only 7 months in T-PLL. Standard therapy of CLL with alkylating agents and prednisone have been not much effective in the treatment of PLL with a response rate of about 20%. Up to date no ideal treatment is available for PLL. A realistic goal is probably to achieve a clinical course transformation, from aggressive to mild, thus changing from short to long term prognosis. For this purpose the initial therapeutic approach cannot be limited to a single agent only. Splenic irradiation, intensive anthracyclines-based regimens, leukapheresis combine together represent the best therapeutic choice. Alkylating agents with or without prednisone may play a role in keeping indolent clinical course. Fludarabine has shown antileukemic activity against PPL even in patients resistant.