Aims and objectives: To explore emergency nurses' perceptions of the feasibility and utility of Pain Assessment in Advanced Dementia tool in people over 65 with cognitive impairment. The Pain Assessment in Advanced Dementia tool was then compared with The Abbey Pain Scale, Doloplus-2 and PACSLAC. The objective was to determine which observational pain assessment tool was the most appropriate for the emergency department context and the cognitively impaired older person. Background: The number of older people with cognitive impairment conditions, such as dementia, presenting to the emergency department is increasing. Approximately 28% of people over 65 years who present will have cognitive impairment. Older people with cognitive impairment often receive suboptimal pain management in the ED. There is limited evidence of the use and/or appropriateness of dementia-specific pain observation assessment tools in the ED. Design: This was a multicentre exploratory qualitative study, which was conducted within a constructivist paradigm. Methods: Focus group interviews were conducted with nurses across three hospital emergency departments. Data were subject to thematic analysis. Results: Six focus groups were conducted with 36 nurses over a 12-week period. Four themes emerged from the analysis: 1) cognitive impairment is a barrier to pain management; 2) PAINAD gives structure to pain assessment; 3) PAINAD assists to convey pain intensity; and 4) selection of an appropriate observational pain assessment tool. Conclusions: This study identified that emergency nurses find it challenging to detect, assess and manage pain in cognitively impaired people. While the use of the PAINAD helped to address these challenges compared to other tools, nurses also identified the important role that family and carers can play in pain assessment and management for older people with cognitive impairment. Relevance to clinical practice: This study has generated new knowledge that has broad application across clinical settings, which can assist to transform pain management practice and reduce human suffering. The use of an observational pain assessment tool can provide for greater practice consistency for patients with communication difficulties. Pain management for older people with cognitive impairment is best achieved by the use an appropriate observational pain assessment tool and with a multidisciplinary approach that includes the person and their family/carer.