Objectives: 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. Design: Multi-center, cross sectional observational study. Setting: Residential Aged Care Facilities. Participants: 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. Measurements: Data was collected from a stratified sample of 229 residential aged care facilities in each state and territory in Australia. Results: 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). Conclusion: 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.