Human epididymis protein 4 (HE4) is a new biomarker for the detection of ovarian cancer. We evaluated the analytical performance of a novel automated HE4 assay and established reference ranges of HE4 and CA125. We also compared the diagnostic performance of both biomarkers for ovarian cancer. Precision performances and linearity of the HE4 assay were assessed. Serum samples from 2,182 healthy and 72 pregnant women were also assayed for HE4 and CA125, and the 95%, 97.5% and 99% reference limits for both markers were calculated. Additionally, sera from 66 ovarian cancer and 257 benign gynecologic disease patients were tested to validate reference ranges and diagnostic performances. The total precision of the HE4 assay was <5% coefficient of variation for most of the levels evaluated. The linearity range of this assay was from 15.0 to 1100.0 pmol/L. The 97.5% upper reference limits for HE4 and CA125 were 33.2 pmol/L (95% confidence interval [CI], 32.2–34.0) and 38.3 U/mL (95% CI, 35.1–41.5), respectively. Using these values as cutoff points, the sensitivity and specificity of HE4 for differentiating ovarian cancer from benign gynecologic diseases and healthy individuals were 90.9% and 94.1%, and those of CA125 were 72.7% and 94.4%. The receiver operating characteristic-area under the curve values of HE4 and CA125 for discriminating ovarian cancer from age-matched control were 0.94 and 0.86, respectively, and they were statistically different (p= 0.0095). The new automated HE4 assay showed good analytical and diagnostic performances. The reference limits established in our study could be used as cutoff levels to facilitate more accurate diagnosis of ovarian cancer in Asian population.