The content of phosphate compounds in blood conserved at 2–4 °C in ACD, ACD with adenosine and ACD with adenosine and persantin has been investigated. The decomposition of high-energy phosphate compounds (and 2,3-DPG) was much slower in the solution containing adenosine withpersantin than in two other media during the 6-week period of blood conservation. The clinical importance of the application of persantin for the prolongation of blood conservation is discussed.