A parasitological survey was made in 1999 and 2002 to determine the magnitude of geohelminthiasis (soil-transmitted helminthiasis) and generate reference baseline helminthological data for Wondo Genet area, southern Ethiopia. Stool specimens were collected using Kato technique from 3167 schoolchildren, 92 schoolteachers, and 1160 residents of two Peasant Associations (PAs) and microscopically examined. The prevalence of infection for Ascaris lumbricoides and Trichuris trichiura among schoolchildren was 83.4% and 86.4%, respectively, and the respective intensity of infection was 7343 eggs per gram of stool (EPG) and 461 EPG. The prevalence of infection for Ascaris lumbricoides, Trichuris trichiura, and Schistosoma mansoni among schoolteachers was 33.7%, 35.9% and 17.4%, respectively, with the respective intensity of 1089 EPG, 194 EPG and 89 EPG. Similarly, the prevalence of infection among the residents of Shesha Kekele and Wondo Wosha Peasant Associations for Ascaris lumbricoides, Trichuris trichiura, and Schistosoma mansoni was 77%, 88% and 30%, respectively, with the respective intensity of 4673 EPG, 452 EPG and 125 EPG. Both the prevalence and intensity of infection were low among the schoolteachers possibly due to a better personal hygiene. The most prevalent soil-transmitted helminth in the area was Trichuris trichiura. Other rare helminths encountered were Taenia species, hookworms, Enterobius vermicularis and Hymenolepis nana, all occurring in less than 4% prevalence of infection. The heavy helminth burden among the schoolchildren calls for immediate intervention to reduce morbidity and transmission of helminthiasis in Wondo Genet.