AIM: To construct and evaluate psychometric properties of the person-centred care of older people with cognitive impairment in acute care settings (POPAC) scale. BACKGROUND: Older people with cognitive impairment are admitted frequently to acute care, with needs not always met through standard practice. Best practice models have been suggested, but few assessment scales exist. METHODS: Psychometric evaluation using statistical estimates of validity and reliability based on an Australian sample of acute care nursing staff (n = 212). RESULTS: The final 15-item questionnaire consists of three subscales, 'using cognitive assessments and care interventions', 'using evidence and cognitive expertise' and 'individualizing care'. Estimates of validity and reliability were highly satisfactory. CONCLUSION: The POPAC scale makes a valuable contribution by providing valid and reliable measures of the extent to which acute nursing staff report using best practice care processes to identify and consider cognitive impairment and to employ nursing interventions to meet the needs associated with old age and cognitive impairment. IMPLICATIONS FOR NURSING MANAGEMENT: The POPAC scale is short, easy to administer and not time consuming to complete, but still provides clinically relevant information. It can be used as a conceptual fundament in developing best practice nursing care in the acute clinical setting, as well as for nursing research.