In Finland, the care of older persons is shifting from institutional care to family care. Research shows that family caregivers experience their situation much in the same way as professional nurses. The nurses' experiences have been studied in terms of vulnerability, and the same perspective could deepen our understanding of family caregivers' experiences. The aim of this study was to gain knowledge of the vulnerability of older caregivers taking care of an ageing family member. The research questions were as follows: How do family caregivers experience vulnerability? How do their experiences relate to vulnerability as understood by nurses? The study was done as a secondary analysis of focus group interviews on the experiences and daily life of older family caregivers. Four caregivers had taken part in monthly interviews during a period of 10 months. The interviews were analysed by deductive and inductive content analysis. The results showed that the caregivers saw caregiving as part of being human. They experienced a variety of feelings and moral agony and were harmed physically, mentally and socially. They showed courage, protected themselves and recognised that being a caregiver also was a source of maturing and developing. These results corresponded with the nurses' understanding of vulnerability. Shame, the experience of duty as a burden, worry and loneliness were themes that were found only among the family caregivers. The use of a matrix may have restricted the analysis, but using it in an unconstrained way allowed for new themes to be created. The results indicate a common humanness and vulnerability in professional and family caregiving. They also show that family caregivers need more support both from society and professionals. [ABSTRACT FROM AUTHOR]