During a 3 year period, from August 1985 to August 1988, 18 HIV 2-infected blood donors were detected in France as a result of systematic HIV 1 screening. These sera were characterized as HIV 2 by specific Western blot and synthetic peptides. Within the same period, 40 other HIV 2 infected subjects were identified by our study group, independently of blood donations. Thirty of these 58 subjects living in France originate from West Africa (8 blood donors), 3 (I blood donor) are Portuguese men who had lived in West Africa and 25 (9 blood donors) are of French origin; among these, 16 have had a known close contact with West Africa. When HIV 2-infected subjects were asymptomatic, cross reactivity between antibodies to HIV 2 and HIV 1 proteins was generally observed with the two-step ELISA assays using total HIV 1 proteins; it was poor with the competitive assays and variable with the assays using recombinant proteins. When the subjects had signs of immunodeficiency, cross reactivity decreased. The data confirm that HIV 2 is not widespread in France and that most of HIV 2-infected but asymptomatic subjects are recognized by several HIV 1 ELISA assays. Accordingly, systematic screening for HIV 2 with an additional test cannot be recommended at the present time, but a combined HIV 1 and HIV 2 test will be useful when available.