BACKGROUND: Helminthiasis is a parasitic disease in human that causes a disturbance in food absorption and lead to malnutrition. The disease slowly impacts on the intelligence. The incidence of helminthiasis in Indonesia remains high, ranging from 2.5% to 62%. A preliminary study found that the proportion of helminthiasis in children is 31.25%. AIM: The aim of the study to analyse the relationship between age, school sanitation and personal hygiene with helminthiasis elementary school children in Juhar Karo Regency in 2019. METHODS: This was an observational study with a cross-sectional design. Subjects were children in grades IV, V and VI with and without helminthiasis. A total of 194 children selected by proportional random sampling were enrolled. Data were collected by interview, observation, and stool examination with the Kato-Katz method. RESULTS: The proportion of helminthiasis in boys was 51.0%, the proportion of poor sanitation in school was 36.6%, and the proportion of poor personal hygiene was 67.5%. CONCLUSIONS: Personal hygiene was significantly associated with the incidence of helminthiasis (RP = 6.052; 95% CI = 3.029-12.902; P-value = 0.001). Improved personal hygiene may prevent the occurrence of helminthiasis. CONCLUSION: The proportion of helminthiasis in elementary school students in this region was 50.0%. Personal hygiene has been shown to be related to helminthiasis. In this study, subjects with poor personal hygiene had a chance of 6.052 times greater to experience helminth infection compared to subjects who had good personal hygiene.