Tehran University of Medical Sciences International Journal of Hematology-Oncology and Stem Cell Research 2008-2207 7 4 2013 12 15 34 39 Akbar Dorgalaleh Hematology Department, Allied Medical School, Tehran University of Medical Sciences, Tehran, Iran. Mohammad Mahmudi Pars Pathobiology laboratory, Minoodasht, Golestan, Iran. Shadi Tabibian Hematology Department, Allied Medical School, Tehran University of Medical Sciences, Tehran, Iran. Zahra Kashani Khatib Hematology Department, Allied Medical School, Tehran University of Medical Sciences, Tehran, Iran. Gholam Hossein Tamaddon Department of laboratory Sciences, faculty of paramedical sciences, Shiraz University of Medical Sciences and Health Servies, Shiraz, Iran. Esmaeil Sanei Moghaddam Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine and Zahedan Regional Educational Blood Transfusion Center, Iran. Taregh Bamedi Parasitology Department, Zahedan University of Medical Sciences, Zahedan, Iran. Shaban Alizadeh Hematology Department, Allied Medical School, Tehran University of Medical Sciences, Tehran, Iran. Eshagh Moradi Medical Education Department, Medical Faculty, University of Medical Sciences, Tehran, Iran. 2015 10 14 Background: Acute renal failure describes as a syndrome by rapid decline in the ability of the kidney to eliminate waste products, regulate acid–base balance, and manage water homeostasis. When this impairment is prolonged and entered chronic phase, erythropoietin secretion by this organ is decreasing and toxic metabolic accumulates and causes hematological changes include decrease of HCT, MCV and RBC and platelet counts. This study evaluates present of anemia and thrombocytopenia in patients with acute and chronic renal failure. Materials and Methods: This study conducted on 132 patients with renal impairment and also 179 healthy individuals as two separated control groups. Initially patients with renal problem were tested and after confirmation of impairment, patients were divided in two groups, acute with less than 3 months and chronic with more than 3 months renal failure, based on duration of the disease. Then complete blood count performed for each patient and finally obtained data were analyzed by SPSS software. Results: Comparison between 96 patients with acute and 36 patients with chronic renal failure revealed that severity of anemia (HCT, Hb and MCV) between these two groups were statistically high in comparison with control groups (P>0.05) but thrombocytopenia in patients with chronic renal failure was statistically different from control and the acute ones (P<0.001). Conclusion: It was recommended that in patients with chronic renal failure, to prevent the risk of bleeding, platelet count should be checked periodically. https://ijhoscr.tums.ac.ir/index.php/ijhoscr/article/view/438 https://ijhoscr.tums.ac.ir/index.php/ijhoscr/article/download/438/359