By now, over billions of people are threatened by the infection of various parasites around the world. Many parasitic pathogens infest not only people, but also domestic animals and even wild animals, and the parasites in animals might be transmitted to people in certain ways. Due to fair lagging economic and living conditions in developing countries, the prevalence of parasitic diseases is far more serious than that in developed countries, but some parasitic diseases became important public health problems due to HIV infection, organ transplantation, and the use of immunosuppressors in the developed countries. Moreover, food-borne parasitic diseases not only affect the health and quality of life of patients, but also bring huge losses to social and economic development. Medical Parasitology is a science that focuses on the parasite-host interaction and diseases caused by parasite invasion. Medical Parasitology studies the functional morphology, development, ecology, prevalence, and the diverse implications of parasitism. This online-course has been fully revised to integrate clinical cases or anecdotal reports about parasites to achieve the knowledge transfer. Bridging the gap between clinical and biological texts, Medical Parasitology appeals to students interested in the medical aspects of parasitology and those who need a solid foundation in the biology of parasites. Medical Parasitology will prepare you for Clinical Medicine study, and Public Health study as well. Our course is divided into the following Chapters: General Introduction, Medical-related Nematode, Cestode, Trematode, Protozoa, and Arthropod. Each chapter has lecture slides, quiz, and extended resources for your off-line learning and discussion. The final exam will test your learning outcome of the entire course.