This research article was published by Elsevier,2022Stunting is the most prevalent form of chronic undernutrition. The Rukwa region in Tanzania has one of the highest prevalence of stunting, despite being one of the most food secure region in the country. It is therefore important to understand other possible environmental and biological factors for stunting/growth failure, apart from food insecurity. This was a hospital based prospective cohort study aimed at assessing other causal relationship between Environmental Enteric Dysfunction (EED), WaSH practices and growth failure in children aged between 1–2 years from Rukwa, Tanzania, using univariate and multivariate logistic regression models. We found very significant causal relationship between growth failure and combined water availability (p = 0.0055), toilet sharing by parents/caregivers (OR = 2.632, CI: 1.156–6.233, p = 0.023 from univariate analysis, and OR = 4.067, CI: 1.484–12.206, p = 0.008 from multivariate analysis), and handwashing by parents/caregivers before food (OR = 3.363, CI: 0.928 -11.454, p = 0.05 from univariate analysis and OR = 15.038, CI:2.422–115.8, p = 0.005 from multivariate analysis). This significant causal relationship may be linked to increased diarrheal incidence and other waterborne infections among the studied children, which may then lead to inadequate absorption of nutrients and subsequent growth failure. The findings herein should therefore improve policy and programs designed to deliver targeted intervention strategies in Tanzania, to also identify and include other entry points for managing child growth failure and improving WaSH services.