BackgroundIntestinal parasites are a common problem in the world. The greater proportion of infections is associated with poor water, sanitation, and hygiene (WASH). This study was conducted to assess intestinal parasites, WASH condition, and their association in rural Dembiya, northwest Ethiopia.MethodsA cross-sectional study was employed. Two hundred twenty-five children aged 6–59 months were included. Mothers were interviewed using a structured questionnaire, and the living environment was observed using checklists. Kato-Katz technique was used to determine the intensity of parasitic infections. Escherichia coli (E. coli) was used as a biological indicator for drinking water quality. Multivariable binary logistic regression analysis was conducted to identify WASH predictors of parasites on the basis of adjusted odds ratio (AOR) with 95% confidence interval (CI) and p < 0.05.ResultsThe prevalence of intestinal parasites was 25.8% (95% CI = 20.3–32.0%). Ascaris lumbricoides (78%), hookworm (12%), Hymenolepis nana (7%), Enterobius vermicularis (5%), Schistosoma mansoni (3%), Giardia lamblia (3%), and Trichuris trichiuria (2%) were identified infections. Intestinal parasites were associated with poor child hand washing practice [AOR = 3.86, 95% CI = 1.53, 9.75], unprotected water sources [AOR = 7.79, 95% CI = 3.30, 18.40], access to water below 20 l/c/d [AOR = 3.05, 95% CI = 1.28, 7.23], poor food safety[AOR = 4.33, 95% CI = 1.62, 11.58], and poor sanitation [AOR = 5.01, 95% CI = 1.56, 16.16].ConclusionA. lumbricoides, hookworm, H. nana, E. vermicularis, S. mansoni, G. lamblia, and T. trichiuria were identified. Child hand washing practice, service level of water supply, water sources, food safety, and sanitation were associated with intestinal parasites. WASH promotion is needed to prevent infections.