It has already been demonstrated that insulin resistance (IR) is associated with the stimulation of erythroid progenitors and with increased levels of inflammation markers. Therefore, IR should also be associated with increased red blood cell (RBC) and white blood cell (WBC) count. The aim of this study is to demonstrate that IR is independently associated with altered hematological parameters in a Brazilian sample. We analyzed laboratorial exams from 925 subjects. All data on hematological parameters, insulin resistance (Homeostasis Model Assessment [HOMA]) and lipid levels were included in the analysis. Demographic information included age and gender. HOMA correlated positively with RBC (r= 0.17, p< 0.001), plasma hemoglobin concentrations (r= 0.14, p< 0.001), hematocrit value (r= 0.15, p< 0.001) and WBC (r= 0.17, p< 0.01). Subjects in the upper quartile of IR had higher levels of plasma glucose, fasting insulin, triglycerides, hematocrit, hemoglobin, RBC and WBC count than those in the lower quartile. In conclusion, IR seems to be associated with alterations in several hematological parameters. These hematological alterations may be considered an indirect feature of the IR syndrome.