Objectives To compare the FRAIL‐NH scale with the Frailty Index in assessing frailty in residential aged care facilities. Design Cross‐sectional. Setting Six Australian residential aged care facilities. Participants Individuals aged 65 and older (N = 383, mean aged 87.5 ± 6.2, 77.5% female). Measurements Frailty was assessed using the 66‐item Frailty Index and the FRAIL‐NH scale. Other measures examined were dementia diagnosis, level of care, resident satisfaction with care, nurse‐reported resident quality of life, neuropsychiatric symptoms, and professional caregiver burden. Results The FRAIL‐NH scale was significantly associated with the Frailty Index (correlation coefficient = 0.81, P < .001). Based on the Frailty Index, 60.8% of participants were categorized as frail and 24.4% as most frail. Based on the FRAIL‐NH, 37.5% of participants were classified as frail and 35.9% as most frail. Women were assessed as being frailer than men using both tools (P = .006 for FI; P = .03 for FRAIL‐NH). Frailty Index levels were higher in participants aged 95 and older (0.39 ± 0.13) than in those aged younger than 85 (0.33 ± 0.13; P = .008) and in participants born outside Australia (0.38 ± 0.13) than in those born in Australia (0.34 ± 0.13; P = .01). Both frailty tools were associated with most characteristics that would indicate higher care needs, with the Frailty Index having stronger associations with all of these measures. Conclusion The FRAIL‐NH scale is a simple and practical method to screen for frailty in residential aged care facilities.