Background Acute hospital admissions among older people often lead to functional decline, increased vulnerability, and disruption to everyday life for both patients and relatives. Aim This study explores factors leading to acute admission among older people from the perspectives of older patients and their relatives. Methods We interviewed older people aged 65 and above during their acute admission. Patients receiving home care and home nursing were included, as they are affected by the complexity of everyday life and are considered at higher risk of hospitalisation. Their relatives participated in a telephone interview on collaboration and care before admission. The interviews were analysed using qualitative content analysis.   Results In total, ten patients and eight relatives were interviewed. The analysis yielded three themes: a) Acute deterioration over time: Both gradual and sudden changes in the health conditions of older people can lead to acute admissions. Distinguishing between these types of changes can be challenging for both older people and their relatives. b) Dilemmas of Delay: Older people and their relatives often hold differing views on the causes of acute hospital admissions and the need for professional care. While some older people downplay or conceal symptoms, relatives must navigate the tension between respecting the older person’s autonomy and acting on their concerns—potentially delaying timely intervention. c) Missed Action: Interactions between older people, their relatives, and health professionals are crucial to care quality, yet missed opportunities for timely intervention may stem from unclear communication, a lack of shared understanding, and relatives’ perceptions of professional approaches as task-focused rather than holistic.   Conclusion Differences between older people and their relatives in the perception of factors leading to acute hospitalisation were identified, particularly regarding severity and urgency. Health professionals must consider the perspectives of both patients and relatives when assessing the health status of older people.