Objective: CLL (Chronic Lymphocytic Leukemia) is the most common form of leukemia in the westernworld and because of prolonged survival of patients, the prevalence is high. Chemotherapy is usually not indicatedin early and stable disease and using Chlorambucil with or without steroids has been the drug of choice in thetreatment of CLL for many years .Clinical studies have shown that using Fludarabin can cause a completeresponse in significant number of untreated and/or previously treated CLL patients. The aim of this study isevaluating of CLL patients and determining the effects of treatment with Fludarabin. Methods: A retrospective(descriptive/cross sectional) study of CLL patients who admitted to Hematology and Oncology Research Centerof Tabriz university of Medical Sciences, between 1995-2005 was made and 126 patients enrolled. Collection ofdata was carried out according to special questionnaire and response to Fludarabin was analyzed by SPSS 11software. Results: The patients mean age of diagnosis was 63.7 years (SD=8.9), 69.8% were males. Illness andfatigue were the commonest presenting symptoms in 54% and lymphadenopathy was the most common clinicalsign in 88.9%.Most of the patients were in stage C in Binet system (52.4%) and/or stage IV in Rai system(44.4%).Chemotherapy with chlorambucil and Prednisolone was the most common regimen used (60.3%) and49.2% of patients were in partial remission with this treatment. Forty two patients treated with Fludarabin and50% were in partial remission, 35% in static disease, 10% in progressive disease and 5% in complete remission(P=0.053). Conclusion: The median survival with Fludarabin was 43.9 months (SD=27.2) and in the case ofChlorambucil+Prednisolone and CVP or Chop it was 45 months (SD=26.5) and 50 months (SD=32.2), respectively(P>0.05). P value in the relationship with survival and response to Fludarabin was more than 0.05.Above all,Fludarabin is the choice treatment as first and second line therapy, as well as for patients who have failedtherapy with standard regimens.