Introduction: We analyzed donor platelet counts and platelet product yields in 708 consecutive platelet aphereses in our program in order to define the importance of this relationship for emerging issues in platelet transfusion therapy. Methods: Aphereses performed on the Spectra 3.6 (COBE, Lakewood, Colo.) the CS-3000 Plus (Fenwall-Baxter, Deerfield, III.) were analyzed. Results: Mean platelet count was 237 ± 49 x 103/mm3 (mean ± SD), and mean yield was 4.24 ± 1.09 x 1011 platelets. Eigthy-five (12%) procedures generated less that 3 x 1011 platelets. Only thirty-eight (5.4%) procedures yielded ≥ 6 x 1011 platelets, so that 'split products' could be obtained. Platelet yields were primarily related to the biologic contribution (baseline platelet count) of the donor. Procedure parameters selected for harvest, and the efficiency of the device also had a significant, but less important role in determining the final platelet yield. An increase in mean donor platelet count achieved with Mpl ligand therapy from 240,000 to 320,000/mm3 would reduce the cost from USD 378 to 267 for each apheresis product, since the fraction of split products would exceed 50% of apheresis procedures. Conclusion: Increasing the donor platelet count would have a significant economic impact on platelet apheresis programs, as well as important clinical consequences for the role of platelet apheresis products in future transfusion strategies.