The prevalence of anti-HAV antibodies declines dramatically in some European countries because of increasing socio-economical level, leaving the adult population susceptible to HAV infection at a higher age. Therefore an increasing proportion of plasma used for preparation of ISG will not contain anti-HAV. So, it seems to us that preselection of donors is necessary for ISG preparation, in order to reach a satisfactory content of anti-HAV. Firstly, 800 donors above 40 years old were selected and it appeared that ISG prepared was not different from ISG coming out of unselected donors. Titer was 200 UI/ml by RIA method. Secondly, we selected plasmas with high titer of anti-HAV: C 10 greater than 87% by a competitive-inhibition RIA. 498 plasmas among 3 050 tested (16%) were chosen to prepare hyper-immune serum globulin (HISG). In this case, anti-HAV level was 800 UI/ml. In these conditions, it is possible to produce hyperimmune globulin that has a known specific potency against HAV and the future prescription would account anti-HAV level and not merely the volume.