Platelet concentrates were prepared from [human] blood collected in CPD [citrate-phosphate-dextrose], CPD-A[adenine]1 and CPD-A3. CPD-A1 contains 1.25 times as much glucose as does CPD, and sufficient adenine to provide a final concentration of 0.25 mM. CPD-A3 contains twice as much glucose as does CPD and sufficient adenine to provide a final concentration of 0.5 mM. The consumption of glucose and production of lactate and pyruvate in the platelet concentrates during room temperature storage was not influenced by glucose or adenine concentration. There was no difference in the rates of fall of the pH of platelets collected in the 3 preservatives. The number of contaminating white blood cells had a significant effect on these parameters. Minimizing the number of contaminating white blood cells in platelet preparations may be an important factor in platelet preservation.