Abstract Platelets are known to undergo shape change, activation, a release reaction and apoptosis/necrosis during processing and storage. Any additional processing, during apheresis may have a deleterious impact on platelet life and functional integrity. Platelet concentrates from 50 volunteers obtained using two blood separators, the Cope Spectra and Fresenius, were observed for platelet activation (CD62 and CD154) and apoptosis (annexin V) to show the effect of aphaeresis and storage. Base line (BL) donor samples taken before separation, during apheresis (DS) and on the third day of storage of the platelet concentrates were collected. Platelet aggregation to ADP and collagen was performed. There was a statistically significant increase in expression of the activation markers in DS samples and the third day samples compared to BL samples and the third day sample, when compared to DS samples. Although the increase in annexin V expression was not so noticeable, it also showed a significant increase. There was a marked decline in the platelet aggregation to both ADP and collagen DS and on the third day of storage. The correlations between the values of CD62, CD154 and Annexin V were detected in BL samples and increased in both DS and on the third day of storage. The correlation between the values of platelet aggregation to collagen and Annexin V was seen only in the BL samples. No other correlations could be detected between platelet aggregation and markers of activation and apoptosis during apheresis and storage. It could be concluded that initial platelet activation, induced by apheeresis, has an impact on PS expression with no impact on the aggregation function of platelets during storage.