Platelet concentrates were prepared from blood of donors by means of Fenwal CS-3000, or by double centrifugation method. Platelets from CS-3000 were cryopreserved with 5% DMSO for 2-4 weeks. After thawing and washing platelets were stored in room temperature for 6 hours. Immediately after plateletapheresis the platelet count decreased by 24% and leukocyte count, Ht and Hb diminished on average 30%, 22% and 18% respectively. The efficiency of separation procedure was 45% and white cells contamination 5.8 +/-8.1 x 10(11). Significant morphological changes and the decrease in total ATP comparing to double centrifugation method were observed. Storage of platelets for 6 hours in room temperature didn't cause their quality changes. Single donor plateletapheresis method can prevent alloimmunization and diminish the risk of transmission of the viruses.