Two new enzymoimmunoassays for FSH and LH adapted to the ES 600 analyzer (Boehringer Mannheim Diagnostics) were evaluated. The limit of detection was below 0.5 mIU/ml. Precision was excellent, the intra-assay coefficients of variation ranged from 1.2 to 2.2%, and the interassay variations from 2.0 to 2.8%. Both methods compared well with other commercial enzyme immunoassays, with correlation coefficients for FSH and LH of 0.988 and 0.974, respectively. There was no interference on the assays by the rheumatoid factor. The results of an external quality control assured the reliability of the measurements. Preliminary reference values were obtained.