['BACKGROUND/ AIM: The prognostic significance of hyperleukocytosis in chronic lymphocytic leukemia (CLL) remains uncertain. The aim of the present study was to evaluate the clinical characteristics and outcome of patients with CLL and white blood count (WBC) >150×10(6)/l at the time of diagnosis.', 'Using the database of the Israeli CLL Study Group, which includes 1,507 cases, we identified 41 patients diagnosed with WBC >150×10(6)/l and analyzed the survival in the group that was 62 months compared to 174 months in patients without hyperleukocytosis (p<0.001). However, multivariate analysis demonstrated that the WBC count had no predictive value in relation to survival time. While in the entire patient cohort advanced age and Binet stage, presence of thrombocytopenia and ZAP-70 expression were independently associated with poor prognosis, these parameters lost their prognostic value in patients with hyperleukocytosis.'] Does absolute lymphocyte count with extreme hyperleukocytosis have a prognostic impact in chronic lymphocytic leukemia?