To determine the proportion of Residential Aged Care Facilities (RACFs) in Australia who use a nutrition screening tool on residents to identify those at risk of malnutrition, and to review practice following identification of residents as being at high risk of malnutrition.Multi-center, cross sectional observational study.Residential Aged Care Facilities.The Director of Nursing at each site was contacted by telephone and asked questions relating to current nutrition screening practices at their residential aged care facility.Data was collected from a stratified sample of 229 residential aged care facilities in each state and territory in Australia.82% of RACFs (n = 188) use a nutrition screening tool on residents to identify those at risk of malnutrition, however only 52% of RACFs (n = 119) used a screening tool which is validated in the residential aged care setting. There was a significant association between facilities using a nutrition screening tool and the staff members being trained to conduct nutrition screening (p < 0.001). Facilities that employed a dietitian were more likely to use a validated nutrition screening tool (p < 0.005). The most frequently used nutrition screening tool was the 'Mini Nutritional Assessment - Short Form (MNA-SF)', which was used by 32% (n = 60) of the RACFs, followed by the 'Malnutrition Universal Screening Tool (MUST)' (15%, n = 29).We found that the majority of RACFs in Australia use a nutrition screening tool, however many of these RACFs use a tool which has not been validated in the RACF setting. This study highlights the need for greater dietetic advocacy in using validated nutrition screening tools to ensure malnutrition is identified.