Background: The endemicity of intestinal and urinary schistosomiasis has long been establishedrnin Ethiopia, and new foci have also been continuously discovered.rnObjective: The objective of this study was to determine the transmission and magnitude ofrnschistosomiasis in Hayk area, Northeastern Ethiopia.rnMethods: A cross sectional parasitological study involving 384 school children was undertakenrnto determine the prevalence of intestinal schistosomiasis between January and March 2010 inrntwo primary schools in Hayk area, Northeastern Ethiopia. Stool samples from 384 school childrenrnwere processed for microscopic examination using Kato-Katz technique. Malacological surveyrnand observation on human water contact activities were also carried out. As a malacologicalrnsurvey snails were checked for schistosome infection by exposing lab-bred mice to the cercariaernshed from Biomphalaria pfeifferi en masse.rnResults: The prevalence and intensity of intestinal schistosomiasis among school children inrnHayk Number 1 and Hayk Number 2 Primary Schools was found to be 45% and 161 epg,rnrespectively. The prevalence of infection had relationship with age and gender. Males are morerninfected than females. Children in the age group 15-19 years had the highest infection rate,rnfollowed by 10-14 and 5-9 years age groups. Schistosome infection in Biomphalaria pfeifferirnwas 3.2%. Schistosome infection was also established in laboratory-bred mice and adultrnSchistosoma mansoni worms were harvested from exposed mice after 6 weeks of maintenance.rnConclusion: The observed intestinal schistosomiasis with prevalence of 45% among youngrnchildren, collection of schistosome infected Biomphalaria pfeifferi, and the establishment of labrninfection in mice showed that transmission of intestinal schistosomiasis is taking place in thernarea. Since the community represents a high risk community, schistosomiasis control should bernimmediately put in place.