Purpose: In order to lower the infection rate and the reinfection rate of Clonorchiasis in high-risk areas, we performed and analyzed a case management on people with chlonorchisis. Methods: The data was collected from April 2010 to March 2011. A community health practitioner was selected as a case manager based on our training program. The intervention group had 58 participants with three months of case management and the control group had 144 participants handled with traditional methods. Results: the pre and post-test in the intervention group and the control group showed us improved knowledge of Clonorchiasis, attitudes and behavior toward eating freshwater fish. The results of post-test between the intervention group and the control group showed statistically significant differences in all categories, except a hand-washing category. However, one year after a case management, there was no significant difference in the failure rate of treatment. Conclusion: The case management was effective for people infected with Clornorchiasis near riverside areas; however, in order to lower the rates of reinfection and treatment failure, it is necessary to perform continuous monitoring and regular evaluations.