Since 1985 all donor blood in the Federal Republic of Germany (FRG) and West Berlin (WB) have been routinely tested for HIV antibodies. The blood donor services of the German and Bavarian Red Cross have pooled their anti-HIV test data for the first year of operation (July 1985-June 1986) to obtain information on the prevalence of HIV antibodies in blood donors and in donated blood. Of 2.27 million units of blood, donated by 1.33 million donors, 218 were anti-HIV positive in the Western Blot Test, i.e. a prevalence rate of 10 per 100,000 donors. The prevalence was, as expected, higher in males than females. During the test period the anti-HIV prevalence fell, both as a total and in all subpopulations. In the second quarter of 1986 it had decreased to 6 per 100,000 donated units.