We studied the ultrastructural morphology and function of platelets collected by apheresis procedure with discontinuous flow using the Surge Pump Technique. The platelet concentrates obtained by this technique are free of erythrocyte and lymphocyte contamination. The platelet morphology as well as the platelet aggregation induced by ADP, adrenaline and collagen of platelet concentrates were similar to those observed in PRP before the apheresis. The response to the hypotonic shock of platelet concentrates was also normal, indicating membrane integrity and good platelet metabolism. These results show that platelet concentrates obtained by the Surge Pump Technique maintain their haemostatic effects and may be infused in thrombocitopenic patients, reducing the risk of alloimmunization related to the presence of erythrocytes and lymphocytes.