Drugs used during anesthesia might induce disturbance on microcirculation due to their systemic cardiovascular actions and to direct hemorheological effects. A comparative investigation of the hemorheological alterations related to in vitro propofol treatment of red blood cells (RBCs) from healthy and diabetic volunteers is presented here. Viscoelasticity and aggregation of RBCs from type 2 diabetic patients (DBT) and healthy donors (HD) were studied from RBCs incubated with propofol near steady-state concentration. 'S parameter', which measures the aggregation degree, was obtained using digital analysis of microscopic images. Erythrocyte viscoelasticity parameters were determined using an Erythrocyte Rheometer. Results obtained from DBT samples showed an increase of 10% or more in aggregation due to the propofol action. The phase shift between erythrocyte response and oscillating shear stress applied at 1 Hz was altered by propofol treatment of erythrocyte from HD and DBT. Propofol could produce slight alterations in the rheological behavior of erythrocyte from HD and DBT, at concentrations near those of steady state. Moreover, this anesthetic could induce an adverse effect in DBT, particularly on erythrocyte aggregation. The observed hemorheologic alteration would increase the possibility of microcapillary obstruction. Hence, this type of study  would prove relevant to avoid possible postoperative complications.