BACKGROUND: With a technical improvement of the assay system, automated immunoassay analyzers for hepatitis B surface antibody (anti-HBs) are widely used. However, some discrepancies between assays are still being reported. We compared the qualitative and quantitative results of three kinds of anti-HBs assays. METHODS: Serum samples were collected from 517 patients and anti-HBs were determined using AxSYM AUSAB, Bayer ADVIA Centaur, and Roche Elecsys assay systems. RESULTS: The concordance rates between the three assays were 95.1% (543/571). The concordance rates were 97.7% between Centaur and Elecsys, 96.3% between AxSYM and Centaur, and 95.6% between AxSYM and Elecsys. Their correlation coefficients for quantitative results were 0.97, 0.94, and 0.93 in the same order. Twenty-eight specimens showed discrepant results, and all of them had antibody values below 31.5 mIU/mL. CONCLUSIONS: Three immunoassays for anti-HBs presented a high concordance and correlation; however, the results should be interpreted with caution, because there were still significant differences between assay methods, especially for a low-level of anti-HBs.