Background: Diarrhoea diseases are among the leading causes of morbidity and mortality in under-five-children (U-5C) in Nigeria. Inadequate safe water, sanitation, and hygiene account for the disease burden. Cases of diarrhoea still occur in high proportion in the study area despite government-oriented interventions. Objective: To determine the hygiene and sanitation risk factors predisposing U-5C to diarrhoea in Ibadan, Nigeria. Methods: Two hundred and twenty pairs of children, matched on age, were recruited as cases and controls over a period of 5 months in Ibadan. Questionnaire and observation checklist were used to obtain information on hygiene practices from caregivers/mothers and sanitation conditions in the households of 30% of the consenting mothers/caregivers. Data were analysed using descriptive and inferential statistics. Results: Caregivers/mothers' mean ages were 31.3 ±7.5 (cases) and 30.6 ±6.0(controls) years. The risk of diarrhoea was significantly higher among children whose mothers did not wash hands with soap before food preparation (OR=3.0, p<0.05), before feeding their children (OR=3.0, p<0.05) and after leaving the toilet (OR=4.7, p<0.05). Factors significantly associated with diarrhoea were: poor water handling (OR=2.0,CI=1.2-3.5), presence of clogged drainage near the house (OR=2.1,CI=1.2-3.7) and breeding places for flies (OR=2.7,CI=1.6-4.7). The mean risk score among cases and controls from the sanitary inspection of drinking water sources were 5.4 ± 2.2 and 3.2 ± 1.9 (p<0.05) and household storage containers were 2.4 ± 1.8 and 1.2 ± 0.7 (p<0.05) respectively Conclusion: Hygiene and sanitation conditions within households were risk factors for diarrhoea. This study revealed the feasibility of developing and implementing an adequate model to establish intervention priorities in sanitation in Ibadan, Nigeria.