Schistosomiasis is a tropical parasitic disease, caused by blood-dwelling worms of the genus Schistosoma. The main human species are S mansoni (occurring in Africa and South America) and S japonicum (South and East Asia) causing intestinal and hepatosplenic schistosomiasis, and S haematobium (Africa) causing urinary schistosomiasis. Severe symptoms develop in predilected people with heavy and long-standing infections. Acute schistosomiasis, a flulike syndrome, is a regular finding in travel clinics. Although prevalences can be high, most infected people show limited, intermittent, or aspecific symptoms. The diagnosis of schistosomiasis relies on microscopic examination of stools or urine, serologic tests, and imaging. Praziquantel is the drug of choice, active against all species in a single or a few oral doses. Current control strategies consist mainly of preventive therapy in communities or groups at risk.