Purpose: This study was done to investigate the prevalence and related factors of Clonorchis Sinensis for inhabitants of the Han riverside area and to identify knowledge related to Clonorchis Sinensis and intended behavioral changes to decrease risk of infection. Method: The data were collected from December 16, 2008 to January 10, 2009. Participants were 555 people who responded to a questionnaire. Frequency, percentage, χ2-test, and t-test were used to analyze the data. Results: The prevalence of Clonorchis Sinensis was 7.9% in this population. Related factors for Clonorchis Sinensis were gender (male=10.8%, female= 3.6%, p=0.002) and smoking (p=0.007). but habits related to ingestion of alcohol and raw fish were not significant. As for knowledge of Clonorchis Sinensis, the Clonorchiasis group had a mean score of 10.09 (±3.95) of a possible 17 compared to a score of only 8.27(±4.60) for the negative group (p=0.011). The intended behavioral change related to risk of infection, according to presence of infection or not, was significant (p=0.004). Conclusion: These results suggest that Clonorchiasis is still highly endemic in all risk areas such as the Han riverside, indicating that it is necessary to set up effective management programs for patient care and prevention of Clonorchis Sinensis.