The Virtual Patient Record (VPR), the union of all collections of health relevant data that accumidates over a person’s lifetime in any institution that person has contact with, is a technical possibility in the age of networked computers[1]. This paper investigates, under what conditions the VPR may be useful and manageable. Quantitative considerations of the VPR for a population of 10 M people form the basis. Dynamic aspects of updating and decay in value for treatment decisions are also taken into account. The role of centralized and distributed data stores are compared and the need for indexing is identified.