Abstract: The study was conducted among school children in Gorgora town, located on the shore of Lake Tana. The objective was to determine the prevalence and intensity of infection. The result showed that, out of 472 students examined, the prevalence of S. mansoni was 29% (95% CI, 27 - 32%). The intensity of infection was moderate (Geometric _ epg = 289). Of the 137 positives, 21.2% had heavy infections (>800 epg). The prevalence and intensity of infection was high in the age group of 10-14 years. Reduction in morbidity is recommended as top priority in the control of schistosomiasis. [Ethiop. J. Health Dev. 1999;13(1):15-19