Hyperleukocytosis (HL) is defined as the clinical condition when the white blood cell (WBC) count is above 100,000/mm(3) in peripheral blood. It has been already shown in the literature that leukapheresis, a conventional technique to decrease the serum WBC level, is ineffective for long-term survival in cases of hyperleukocytotic acute myeloid leukemia (AML) with leukostasis. However, the effect of leukapheresis on early mortality is still unclear. In this study, we aimed to evaluate the effect of leukapheresis on early mortality of patients with AML who have HL. Twenty-eight de novo patients with AML, diagnosed with HL between 2002 and 2015 at the Hacettepe Hematology Department, were analyzed retrospectively. Leukapheresis was performed in 10 patients, and the mean WBC decrease with leukapheresis was 57.4 x 10(3)/mu l which accounts for 31% of the initial WBC count. The indications for leukapheresis were hyperviscosity and prophylaxis in four and six patients, respectively. In the group of patients who received leukapheresis, three of four patients who had hyperviscosity symptoms died, and three of six patients died who did not have symptoms. In our study, we observed that the leukapheresis procedure is highly effective in reducing plasma WBC levels. However, although it is statistically insignificant, our findings also revealed that there is a much higher rate of death in patients who were treated with leukapheresis. Therefore we conclude that leukapheresis does not lower rates of early death; nevertheless, this finding should be confirmed by prospective studies with larger cohorts. (C) 2017 Elsevier Ltd. All rights reserved.