Centrifugal devices for donor plasmapheresis that collect platelets as a by-product have recently been introduced. The platelet yield ranges from 1.2 to 2 X 10(11) per collection, and the collection time exceeds 50 minutes. An attempt to increase yields and to reduce the procedure time was carried out at our center, taking advantage of the Dideco Eccentriplate (Dideco spa, Mirandola, Italy). Within 30 minutes, 510 ml of plasma were collected along with 3.3 X 10(11) platelets. The shift of donors from whole blood to plasma and platelet donation generated a progressive decrease in red-cell availability. In order to maintain plasma and platelet production without affecting the erythrocyte production, a technique was developed that allows the collection of 3.68 X 10(11) platelets, 250 ml of plasma, and 225 ml of packed red blood cells with a hematocrit of 66.5%. The mean procedure time was 31.6 minutes; 2,671 ml of blood were processed at flow rates of 85-100 ml/minute. The cellular cross contamination of the platelet concentrates was 1.76 X 10(8) (leukocytes) and 2.23 X 10(8) (erythrocytes). Although the procedure was carried out in a selected group of donors, the technical experience has strongly modified our procedure for platelet and plasma collection.