Background: Chronic lymphocytic leukemia (CLL) is one of the chronic lymphoproliferative disorders. Many drugs were used for treatment of CLL, but efficacy of them is controversy. In present study, we compare survival of patients with CLL in three treatment regimens of fludarabine, chlorambucil and cyclophosphamide. Methods & Materials: In this historical cohort study, 83 patients with CLL whom participated in imposed war, enrolled to study. Of these, 39 patients received fludarabine (F), 23 patients received prednisone plus chlorambucil (C), and 21 patients received CAP (cyclophosphamide, doxorubicin, and prednisone). Overal survival (OS), Progression Free Survival (PFS), Complete Remission (CR), Partial Remission (PR) and Overall Remission (OR) were evaluated. For comparison, data entered to SPSS-18 & has been analyzed. P-value<0.05 were significant. Result: With a median follow up of 51 months, 16 (19.3%) patients died. Of this, 6 received Fludarabine, 5 received Chlorambucil, and 5 received CVP (P=0.688). PR rates in F, C, and CVP were 53.8%, 30.4% and 42.9%, respectively (p=0.039). CR rates in F, C and CVP group were 23.1, 21.7 and 23.8 percent, respectively (p=0.986), and OR rates were 76.9, 52.2 and 66.7, respectively (p=0.132). Conclusion: According to the results of this study, survival and CR were similar between the three arms of the study. But PR was higher in patients received fludarabine. Comparing results of present study to others, fludarabine has more efficacies on CLL and also suggested as first line treatment.