In gerontology and care research, care is often studied in ways in which older people and people with disabilities are portrayed as dependent on the care of younger or non-disabled people. This thesis, in contrast, studies care provided by people that are both old and have physical disabilities.The thesis explores how care is actualized and experienced by older couples who both have long-term or lifelong disabilities and investigates the implications of this caring in the couples' lives. Nine couples between 60 and 84 years old, of whom most had had disabilities for over 20 years, were interviewed as dyads; a process also conjoint interviewing. These interviews were analysed using grounded theory methods of coding and constant comparison. The results of the thesis confirm that it can make sense to be a carer even if one also needs care in everyday life. Meanwhile, the analysis also considers how conjoint interviewing resulted in relational and performative data about mutual care. The study helps explain the significance helping a partner despite having other sources of formal support and the difficulties of providing this help oneself. Finally, in a study whose participants are growing old together with disabilities, the results also show that the couples could regard themselves as ageing advantageously compared to other groups.Through its focus on caring for and by older people with disabilities, this thesis is at the intersection of social gerontology, care research and disability studies. However, from its interdisciplinary perspective, it can also challenge established discourses in these fields. Specifically, the study problematizes the absence of a care discourse in disability studies and the mostly age-and functioncoded ways in which care is discussed in care research. The thesis problematizes dichotomies used in understanding care, such as roles of carers/care receiver, caring/servicing and dependence/independence. It also challenges established ways of thinking about successful ageing. Lastly, the thesis contributes to the still growing literature on ageing with a disability.