Background: Sickle cell disease (SCD) is characterized by a hypercoagulable state as a result of multiple factors, including chronic hemolysis and the presence of circulating cell-derived microparticles (MPs). The cellular origin of such MPs and the exact mechanism by which it enhance coagulation in SCD are not fully understood.Objective:The study aimed to clarify the presence of circulating erythrocyte-derived MPs in SCD patients during painful crisis and in steady state and the impact of these MPs on coagulation activation and fibrinolysis.Methods: Peripheral blood samples from 25 SCD patients during painful crisis and in steady state were studied for the presence of erythrocyte-derived MPs using flowcytometry. Estimation of D-dimer level as a marker of coagulation activation was done using semiquantitative assay. 36 healthy individuals, age and sex matched, were included as a normal control group. Results:The level of erythrocyte-derived MPs was significantly higher in SCD patients during crisis compared to the control group (p=0.02), but no statistically significant difference was found between erythrocyte-derived MPs level in SCD in steady state and the normal controls or between SCD patients during crisis and in steady state, p=0.3 and p=0.49, respectively. D-dimer level was higher in SCD patients both during crisis and in steady state compared to normal controls (p<0.001).Conclusion: SCD is associated with increased levels of erythrocyte-derived MPs which may contribute to the hypercoagulable state observed in such group of patients.