Introduction: The prevalence and distribution of intestinal helminths varies from place tornplace in Ethiopia. Intestinal parasitic infections have detrimental effects on the survival,rnappetite, growth and physical fitness, school attendance and cognitive performance of schoolrnage children. Higher parasitic disease rates occur in children with infection frequently foundrnin those under 14 years in many risk areas due to poor hygiene and play habits.rnObjective: To determine prevalence and associated factors of intestinal helminthic infectionsrnamong Umolantie primary school children, South Ethiopia.rnMethodology: A cross-sectional study, involving 405 schoolchildren, was conductedrnbetween Nov, 2010 and Jan, 2011. Systematic random sampling technique was applied.rnInterviews and observation were used to identify the risk factors. Stool specimens werernexamined using the Kato-Katz technique. Data was entered and analyzed using SPSS 16.0rnand odds ratio, confidence intervals and p-value were calculated.rnResults: six species of intestinal helminths were identified with an overall prevalence ofrn26.9% (109 of 405 children). The predominant parasites involved were hookworm spp.rn59(14.6%) and S. mansoni 51(12.6%). Prevalence of S. mansoni infection was significantlyrnhigher in males (p=0.006), whereas hookworm infection was significantly higher in femalesrn(P=0.015). Bathing in the stream was strongly associated with higher prevalence of S.rnmansoni infection (p=0.03). Other helminths found were E. vermicularis 1% (4 cases),rnwhipworm 1.5% (6 cases) and tapeworm 1.5% (6 cases) and A. lumbricoide 0.5% (2 cases).rnConclusion and recommendation: A high percentage of primary school children fromrnUmolantie have intestinal helminth infections and majority of them have hookworm and S.rnmansoni. Hence the community should be provided with safe water and should upholdrnawareness about the main routes of transmission of intestinal helminthes. School childrenrnshould avoid water contact habits in the nearby stream and regular shoe wearing habits shouldrnalso be developed among them.rnKey words: geohelminths, S. mansoni, school children, Umolantie, South Ethiopia