For the assessment of the situation after streptococcal infection and thus for prevention of rheumatic fever and glomerulonephritis more simple and rapid serological tests are needed. The principle of indirect haemagglutination seems particularly suited for this purpose. A rapid slide test (streptozyme) for the simultaneous detection of antibodies against five streptococcal enzymes in capillary blood or serum was compared to four monospecific tests: latex-Asl, Antistreptolysin-O (ASL-O), antistreptokinase and anti NADase. Several lots of test kits and more than four hundred sera of adults and children with and without suspected rheumatic fever were tested. The number of falsely negative and falsely positive results was small as compared to single monospecific tests. Additional positive reactions were obtained when the ASL-O was within the normal range, but the titer against several exoenzymes were elevated, or, when the antibodies against a single exoenzyme were extremely strong. The precision of the polyvalent test may not be quite as high as if three monospecific tests are applied, It is however sufficient. Thus it seems unrealistic to require the performance of at least three monospecific tests under the present epidemiological conditions.