Schistosomiasis is one of the most widely distributed parasitic infections in tropical and subtropical countries including Ethiopia. Its importance both in terms of economic development and public health in endemic areas is enormous. A cross-sectional study aimed to assess the prevalence of schistosomiasis and its associated risk factors was conducted from December 2016 to May 2017 among 403 school students in Addis Zemen town, northwest, Ethiopia. Stratified random sampling technique was used to select school students, aged 5-24 years old and grade levels 1-10. Stool samples were collected in clean containers and examined microscopically using direct wet mount and formol-ether concentration methods for the diagnosis Schistosoma mansoni infection and urine samples were also collected and examined using sedimentation method for diagnosis of Schistosoma haematobium. A questionnaire survey was also administered to identify possible risk factors of infection with schistosomiasis. Furthermore, malacological survey was conducted to identify snail intermediate species in the study area. Data were entered and analyzed using the statistical package for social science (SPSS) Version 21.0 software. Of the total 403 school children examined for schistosomiasis, 76 (18.9%) were found to be positive for S. mansoni infection, while no case for S. haematobium was detected.The present study showed a higher prevalence of the disease among elementary school than secondary high school students. Being male (AOR=3.109), age group of 10-14 years (AOR=32.375), grade from 1-8 (AOR=12.201), low awareness about prevention methods of schistosomiasis (AOR=8.424), washing clothes or utensil in river water (AOR=38.183), swimming always (AOR=16.969), bathing in river (AOR=8.852), proximity to river water (AOR=3.11), absence of latrine at school (AOR=3.730) were significantly associated with S. mansoni infection (P<0.05). Educational status and monthly income of students’ family, lack of Knowledge about schistosomiasis, crossing water bodies, frequency of water contact, and presence of dam or stream/spring in the locality, practice in irrigation and absence of latrine at home were not significantly associated with S. mansoni infection. According to WHO category, the prevalence of S. mansoni in this study was at moderate risk.Thus; all primary school age children of Addis Zemen town should be treat once every two years with Praziquantel.School children should be educated to avoid contact with river water and also public health education should be given for the communities.Families should encourage their children to use latrine properly and keep personal hygiene.