Background: The sexually transmitted infection (STI) syphilis remains a public health problem globally. The serological detection of specific antibodies to Treponema pallidum is particularly important in the diagnosis of syphilis. The purpose of this study was to evaluate the newly developed Elecsys Syphilis assay and compare it with the local market well-established ARCHITECT Syphilis TP assay.<br />Methods: A total of 1,097 clinical serum samples were obtained from routine diagnostic requests. All the serum or plasma samples were tested in parallel by Elecsys Syphilis assay and ARCHITECT Syphilis TP assay. Sensitivity, specificity, and agreement assay were verified. The inconsistent samples confirmed with a recombinant immunoblot assay as gold standard test.<br />Results: The diagnostic performances of the two assays were very similar: both Elecsys Syphilis and ARCHITECT Syphilis TP assay performed with a sensitivity of 100% (95% CI, 85.7 to 100%) and 100% (95% CI, 85.7 to 100%), whereas the specificity was 99.90% (95% CI, 99.5 to 99.90%) and 99.49% (95% CI, 99.0 to 99.6%), respectively. The consistency in positive results between Elecsys and ARCHITECT Syphilis TP assay was 79.3%. The consistency in negative results between Elecsys and ARCHITECT Syphilis TP assay was 99.7%. The overall consistency between Elecsys and ARCHITECT Syphilis TP assay was 99.1%.<br />Conclusions: The Elecsys Syphilis assay can demonstrate excellent diagnostic sensitivity and specificity and correlate well with ARCHITECT Syphilis TP assay. It is a reliable and appropriate assay for routine use in a diagnostic laboratory.<br />