Differences in larvicidal activity of complement and chemiluminescent response of phagocytes in carp (Cyprinus carpio), crucian carp (Carassius auratus) and false dace (Pseudorasbora parva) against excysted metacercariae of Clonorchis sinensis were investigated. The prevalence of C. sinensis metacercariae of false daces caught at Nakdong river (NR) was 100%. However, no C. sinensis metacercariae were found in false daces, which were collected at a reservoir in Chinyoung (CY), crucian carps and carps. The sera of false dace, which were intensively infected with C. sinensis metacercariae, killed excysted metacercariae of C. sinensis more readily than that of carp. However, the serum obtained from C. sinensis metacercariae-free false dace showed the lowest larvicidal ability. The larvicidal ability of sera collected from each fish species completely disappeared when the complement was inactivated by heating. When supernatant of excysted metacercariae homogenate were added to phagocytes of each species, the chemiluminescent responses were significantly (p<0.05) diminished in false dace and carp. The inhibition ratio of chemiluminescent responses by the supernatant was 22.9% in false dace, 9.6% in crucian carp and 12.4% in carp.