Background: To assess the potential of AFP-L3% for the utility to diagnose malignant tumors. Methods: AFP-L3 was concentrated from clinically-collected serum samples via the Hotgen Biotech glycosyl cap -ture spin columns and then measured through the protein microarrays. The levels of AFP and AFP-L3 were de-tected by electrochemiluminescence immunoassay. In this retrospective study, 266 patients with the level of serum AFP-L3 over 1 ng/mL were recruited from December 2014 through April 2019. Among them, 155 patients were clinically diagnosed/confirmed with malignant tumors, including 101 hepatocellular carcinomas, 47 stomach ma-lignant tumors, and 7 other malignant tumors; and the rest of 111 patients were nonmalignant tumors. Results: Patients with serum AFP-L3 level of greater than 1 ng/mL were mainly detected in hepatic diseases, in-cluding hepatocellular carcinoma, cirrhosis and chronic hepatitis. In patients with no tumors, the levels of serum AFP-L3 over 1 ng/mL were only observed in liver disease. The levels of AFP-L3 in blood were substantially great-er in patients with HCC. Among the malignant tumor patients with the level of serum AFP-L3 over 1 ng/mL, HCC accounted for 60%, gastric cancer for nearly 40%. The AFP, AFP-L3, and AFP-L3% in blood were in-creased significantly in patients with liver malignancy, chronic liver disease, and cirrhosis. However, the elevation of AFP-L3 and AFP-L3% in the malignant cohort was more evident than that in the nonmalignant counterpart. Conclusions: AFP-L3 is likely to contribute to the differential diagnosis of HCC as well as other hepatic diseases. AFP-L3% is a reliable indicator for diagnosing benign and malignant tumors.