Objective: Propofol is an intravenous general anesthetic with a primary hypnotic effect. Memantine is an NMDA receptor antagonist that has been shown to reverse changes in memory and synaptic plasticity in animal models. This study aims to investigates whether propofol and/or memantine has any effects on erythrocyte deformability. Methods: 24 Wistar albino rats were divided randomly into four groups. Group P received 150 mg.kg(-1) propofol intraperitoneally (ip); Group M received 1 mg.kg(-1) memantine (ip); Group PM received 1 mg.kg(-1) memantine mg.kg(-1) ip 30 minutes before the administration of 150 mg.kg(-1) propofol; and the control group (Group C) received saline ip. Euthanasia was performed in all rats by using intraabdominal blood uptake. The heparinized whole blood samples were used to prepare erythrocyte suspensions, from which erythrocyte suspensions were formed with a PBS buffer solution containing 5 % htc, and the deformability parameters were measured. Results: Erythrocyte deformability was significantly higher in Groups P, M and PM when compared to the Group C(p = 0.007 and p = 0.001, p<0.0001, respectively); while the erythrocyte deformability indices were similar in groups P, M and PM. Conclusion: The administration of propofol and memantine altered the erythrocyte deformability in the rats, which may lead to further problems in microcirculation. The administration of memantine to the propofol-treated rats did not alter the erythrocyte deformability; however the early results should be verified through further experimental and clinical studies (Fig. 1, Ref. 23). Text in PDF www.elis.sk.