This study was to evaluate responsiveness to IFN-alpha and investigate the benefits of sustained response (SR) in patients who were presumed as being vertically transmitted in Korea. A total of 46 patients of presumed vertical transmission with biopsy-proven HBeAg-positive chronic HBV infection were treated with IFN-alpha and followed. We tried to find the factors associated with SR and compared the cumulative rate of HCC and survival between SR group and non-sustained/non-responder (NSR) group. HBeAg loss was acquired in 35% (16/46) within a year but SR was observed in 22% (10/46). Age <35 years and ALT levels >7xULN were significant favorable factors for SR (OR 0.56, 0.49, 95%CI 0.38-0.82, 0.29-0.81, respectively) (both P<0.05). There were no significant differences of cumulative HCC-free survival (100 vs. 68% at 12 years, P=0.36) and survival (100 vs. 73% at 12 years, P=0.3) between SR group and NSR group. In conclusion, age below 35 years old and serum ALT levels above 7xULN may predict IFN-alpha therapy-induced SR among them, although we cannot affirm the effects on HCC prevention or survival.