The performance of a newly devised method employing recombinant antigens for the determination of antibodies to streptolysin O and DNase B on the Beckman Coulter IMMAGE System was compared with a nephelometric assay using conventional antigens. Sera from 114 patients with or without evidence of streptococcal infection were analysed by the two techniques. The results obtained with the new method correlated well with those of the reference test. The sensitivity of a combination measurement of antibodies to streptolysin O and DNase B was higher than that obtained when measuring each parameter alone. Handling of the tests was easier on the Beckman Coulter IMMAGE System. In conclusion, the new test from Beckman Coulter for the measurement of antibodies to streptolysin O and DNase B performs well and equals measurements using conventional antigens on a nephelometer.