BACKGROUND: Fecal occult blood tests (FOBTs) have been widely used as a means of colorectal cancer screening. Automated FOBTs using immunologic principles have the advantages such as quantitation, high specificity, and high throughput. We evaluated a newly-introduced automated FOBT analyzer, OC-SENSOR neo (OC neo) (Eiken Chemical Co., Japan). METHODS: The precision, linearity, and carry-over rate of OC neo were assessed with specimens prepared in accordance with the guidelines of CLSI. We performed a parallel test between OC neo and OC-SENSOR I (OC I) (Eiken Chemical Co.) using 300 consecutive stool specimens and 60 OC I-positive specimens. The results were analyzed with SPSS version 13.0 (SPSS Inc., USA). RESULTS: The coefficients of variation (CV) of within-run, between-run, and between-day using OCControl L (Eiken Chemical Co.) of ca. 150 ng/mL were 3.5-7.8%, 4.5-8.8% and 4.9-5.0%, respectively. The linear regression coefficient and carry-over rate with the range of 67.8-939.4 ng/mL were 0.9998 (P<0.001), and 0.1%, respectively. Correlation coefficient between OC neo and OC I was R(2)=0.954 (P<0.001) for 60 OC I-positive specimens. The positive and negative interpretations of 300 consecutive specimens by OC neo were completely consistent with those of OC I. CONCLUSIONS: Because OC neo showed an excellent performance and a good correlation with OC I, OC neo warrants to be a reliable quantitative FOBT system for high volume laboratories.