A vaccination was performed in ICRmice (n = 10) by subcutaneous injection with 50 g of rFgSAP-2 combined with Freund’s adjuvant. At 2weeks after the second boost, mice were infected with 30 F. gigantica metacercariae by oral route. Thepercentages of protection of rFgSAP-2 vaccine against F. gigantica were estimated to be 76.4–78.5% whencompared with non vaccinated-infected and adjuvant-infected controls, respectively. The antibodies inimmune sera of vaccinated mice were shown by immuno-blotting to react with native FgSAP-2 in theextract of 2- and 4-week-old juvenile parasites. By determining the levels of IgG1 and IgG2a in the immunesera, which are indicative of Th2 and Th1 immune responses, it was found that both Th1 and Th2 humoralimmune response were significantly increased in rFgSAP-2 immunized group compared with the controlgroups, with higher levels of Th2 (IgG1) than Th1 (IgG2a). The levels of serum aspartate aminotransferase(AST) and alanine transaminase (ALT) in rFgSAP-2-immunized group showed no significant difference from those of the non-immunized and infected group, indicating that early juvenile parasites induced liver parenchyma damage, even though the numbers of worm recoveries were significantly different This study indicates that rFgSAP-2 has a high potential as a vaccine candidate against F. gigantica in mice,and this potential will be tested in larger economic animals.