Aim: The aim of this study was to determine the frequency of iron deficiency anemia in patients with severe anemia, and to investigate and compare the difference in the hematological parameters between patients with and without iron deficiency anemia.Material and Methods: A total of 119 patients diagnosed with severe anemia between January 2012 and July 2014 were retrospectively analyzed in this study. Demographic and clinical characteristics of severe anemia patients were evaluated. Patients were evaluated in terms of iron deficiency anemia, and clinical characteristic and laboratory findings of the patients with and without iron deficiency anemia were compared.Results: Of the 119 cases 49 (41.2%) were male and 70 (58.8%) were female, mean age was 6.7±6.2 years. Various comorbidities were present in the patients. In all patients, the group with a hemoglobin value below 6 g/dL had a significantly lower platelet count than those equal to or above 6 g/dL (p=0.037). It was found that 52 (43.7%) of all cases had iron deficiency anemia and 27 (51.9%) of them were aged 5 to 18 years. Patients with iron deficiency anemia had lower ferritin level (p<0.001) than patients without iron deficiency anemia, while platelet count was higher in patients with iron deficiency anemia (p=0.001).Conclusion: In patients with severe anemia, a significant decrease in platelet count was found with hemoglobin value below 6 g/dL. In order to reduce the need for red blood cells transfusion, early diagnosis of iron deficiency anemia is important and iron supplementation should be given earlier.